diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9477b6c0b..f59332b9a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ Changes:
 - Adjust output for Ledger saninity checks
 - Expand exported `bigint` constants to match with those in `BN`
 - Upgrade dependencies to latest stable versions
+- Adjust internal character maps to operate on `Uint8Array` instad of `Array<number>`
 
 
 ## 10.2.6 Jan 13, 2023
diff --git a/packages/util-crypto/src/blake2/asU8a.spec.ts b/packages/util-crypto/src/blake2/asU8a.spec.ts
index 003fecf44..f8e88b93d 100644
--- a/packages/util-crypto/src/blake2/asU8a.spec.ts
+++ b/packages/util-crypto/src/blake2/asU8a.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { blake2AsU8a } from '.';
 
 describe('blake2AsU8a', (): void => {
@@ -61,7 +61,7 @@ describe('blake2AsU8a', (): void => {
   });
 
   describe.each([256, 512] as (256 | 512)[])('bitLength=$p', (bitLength): void => {
-    performanceWasm(`blake2AsU8a, bitLength=${bitLength}`, 64000, (input, onlyJs) =>
+    perfWasm(`blake2AsU8a, bitLength=${bitLength}`, 64000, (input, onlyJs) =>
       blake2AsU8a(input, bitLength, null, onlyJs)
     );
   });
diff --git a/packages/util-crypto/src/ed25519/sign.spec.ts b/packages/util-crypto/src/ed25519/sign.spec.ts
index ad2bb6e39..478c9c886 100644
--- a/packages/util-crypto/src/ed25519/sign.spec.ts
+++ b/packages/util-crypto/src/ed25519/sign.spec.ts
@@ -4,7 +4,7 @@
 import { stringToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { ed25519PairFromSeed, ed25519Sign } from '.';
 
 const PAIR = ed25519PairFromSeed(
@@ -30,7 +30,7 @@ describe('ed25519Sign', (): void => {
     });
   });
 
-  performanceWasm('ed25519Sign', 250, (input, onlyJs) =>
+  perfWasm('ed25519Sign', 250, (input, onlyJs) =>
     ed25519Sign(input, PAIR, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/hmac/shaAsU8a.spec.ts b/packages/util-crypto/src/hmac/shaAsU8a.spec.ts
index b61f4e727..e37e950da 100644
--- a/packages/util-crypto/src/hmac/shaAsU8a.spec.ts
+++ b/packages/util-crypto/src/hmac/shaAsU8a.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a, stringToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { hmacShaAsU8a } from '.';
 
 describe('hmacShaAsU8a', (): void => {
@@ -32,7 +32,7 @@ describe('hmacShaAsU8a', (): void => {
       });
     });
 
-    performanceWasm(`hmacShaAsU8a, bitLength=${bitLength}`, 16000, (input, onlyJs) =>
+    perfWasm(`hmacShaAsU8a, bitLength=${bitLength}`, 16000, (input, onlyJs) =>
       hmacShaAsU8a(input, input, bitLength, onlyJs)
     );
   });
diff --git a/packages/util-crypto/src/keccak/asU8a.spec.ts b/packages/util-crypto/src/keccak/asU8a.spec.ts
index 031a7a9c8..a8580b55f 100644
--- a/packages/util-crypto/src/keccak/asU8a.spec.ts
+++ b/packages/util-crypto/src/keccak/asU8a.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a, stringToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { keccakAsU8a } from '.';
 
 describe('keccakAsU8a', (): void => {
@@ -43,7 +43,7 @@ describe('keccakAsU8a', (): void => {
       });
     });
 
-    performanceWasm(`keccakAsU8a, bitLength=${bitLength}`, 128000, (input, onlyJs) =>
+    perfWasm(`keccakAsU8a, bitLength=${bitLength}`, 128000, (input, onlyJs) =>
       keccakAsU8a(input, bitLength, onlyJs)
     );
   });
diff --git a/packages/util-crypto/src/pbkdf2/encode.spec.ts b/packages/util-crypto/src/pbkdf2/encode.spec.ts
index a067fec71..559985dd2 100644
--- a/packages/util-crypto/src/pbkdf2/encode.spec.ts
+++ b/packages/util-crypto/src/pbkdf2/encode.spec.ts
@@ -5,7 +5,7 @@ import { u8aEq, u8aToHex } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
 import { randomAsU8a } from '../random/asU8a';
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { pbkdf2Encode } from '.';
 
 const KNOWN_SALT = new Uint8Array([
@@ -42,7 +42,7 @@ describe('pbkdf2Encode', (): void => {
     });
   });
 
-  performanceWasm('pbkdf2Encode', 8, (input, onlyJs) =>
+  perfWasm('pbkdf2Encode', 8, (input, onlyJs) =>
     pbkdf2Encode(input, input, undefined, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/scrypt/encode.spec.ts b/packages/util-crypto/src/scrypt/encode.spec.ts
index 515d199b9..a0d5ef978 100644
--- a/packages/util-crypto/src/scrypt/encode.spec.ts
+++ b/packages/util-crypto/src/scrypt/encode.spec.ts
@@ -3,7 +3,7 @@
 
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { DEFAULT_PARAMS } from './defaults';
 import { scryptEncode } from '.';
 
@@ -30,7 +30,7 @@ describe('scryptEncode', (): void => {
     });
   });
 
-  performanceWasm('scryptEncode', 4, (input, onlyJs) =>
+  perfWasm('scryptEncode', 4, (input, onlyJs) =>
     scryptEncode(input, input, undefined, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/secp256k1/compress.spec.ts b/packages/util-crypto/src/secp256k1/compress.spec.ts
index 3a4251d6e..a95cd1a9a 100644
--- a/packages/util-crypto/src/secp256k1/compress.spec.ts
+++ b/packages/util-crypto/src/secp256k1/compress.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { secp256k1Compress } from '.';
 
 describe('secp256k1Compress', (): void => {
@@ -36,7 +36,7 @@ describe('secp256k1Compress', (): void => {
     });
   });
 
-  performanceWasm('secp256k1Compress', 100000, (input, onlyJs) => secp256k1Compress(input, onlyJs),
+  perfWasm('secp256k1Compress', 100000, (input, onlyJs) => secp256k1Compress(input, onlyJs),
     [[
       hexToU8a('0x04b9dc646dd71118e5f7fda681ad9eca36eb3ee96f344f582fbe7b5bcdebb1307763fe926c273235fd979a134076d00fd1683cbd35868cb485d4a3a640e52184af')
     ]]
diff --git a/packages/util-crypto/src/secp256k1/expand.spec.ts b/packages/util-crypto/src/secp256k1/expand.spec.ts
index 2e8f62c16..3471e4e52 100644
--- a/packages/util-crypto/src/secp256k1/expand.spec.ts
+++ b/packages/util-crypto/src/secp256k1/expand.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { secp256k1Expand } from '.';
 
 describe('secp256k1Expand', (): void => {
@@ -36,7 +36,7 @@ describe('secp256k1Expand', (): void => {
     });
   });
 
-  performanceWasm('secp256k1Expand', 2000, (input, onlyJs) => secp256k1Expand(input, onlyJs),
+  perfWasm('secp256k1Expand', 2000, (input, onlyJs) => secp256k1Expand(input, onlyJs),
     [[
       hexToU8a('0x03b9dc646dd71118e5f7fda681ad9eca36eb3ee96f344f582fbe7b5bcdebb13077')
     ]]
diff --git a/packages/util-crypto/src/secp256k1/pair/fromSeed.spec.ts b/packages/util-crypto/src/secp256k1/pair/fromSeed.spec.ts
index 5e69f9c48..2f4e1d11c 100644
--- a/packages/util-crypto/src/secp256k1/pair/fromSeed.spec.ts
+++ b/packages/util-crypto/src/secp256k1/pair/fromSeed.spec.ts
@@ -5,7 +5,7 @@ import { hexToU8a, u8aToHex } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
 import { mnemonicToMiniSecret } from '../../mnemonic';
-import { performanceWasm } from '../../test/performance';
+import { perfWasm } from '../../test';
 import { secp256k1PairFromSeed } from '..';
 
 // mnemonic, secret, public, account_id
@@ -65,7 +65,7 @@ describe('secp256k1PairFromSeed', (): void => {
     });
   });
 
-  performanceWasm('secp256k1PairFromSeed', 500, (input, onlyJs) =>
+  perfWasm('secp256k1PairFromSeed', 500, (input, onlyJs) =>
     secp256k1PairFromSeed(input, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/secp256k1/recover.spec.ts b/packages/util-crypto/src/secp256k1/recover.spec.ts
index 592a2c6a7..05aeedfe3 100644
--- a/packages/util-crypto/src/secp256k1/recover.spec.ts
+++ b/packages/util-crypto/src/secp256k1/recover.spec.ts
@@ -5,7 +5,7 @@ import { u8aToHex, u8aToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
 import { keccakAsU8a } from '../keccak';
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { secp256k1Recover } from '.';
 
 const sig = u8aToU8a('0x7505f2880114da51b3f5d535f8687953c0ab9af4ab81e592eaebebf53b728d2b6dfd9b5bcd70fee412b1f31360e7c2774009305cb84fc50c1d0ff8034dfa5fff');
@@ -25,7 +25,7 @@ describe('secp256k1Recover', (): void => {
     });
   });
 
-  performanceWasm('secp256k1Recover', 200, (_, onlyJs) =>
+  perfWasm('secp256k1Recover', 200, (_, onlyJs) =>
     secp256k1Recover(msg, sig, 0, undefined, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/secp256k1/sign.spec.ts b/packages/util-crypto/src/secp256k1/sign.spec.ts
index cd57f2667..7645c0e52 100644
--- a/packages/util-crypto/src/secp256k1/sign.spec.ts
+++ b/packages/util-crypto/src/secp256k1/sign.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { secp256k1PairFromSeed, secp256k1Sign } from '.';
 
 const pair = secp256k1PairFromSeed(hexToU8a('0x4380de832af797688026ce24f85204d508243f201650c1a134929e5458b7fbae'));
@@ -29,7 +29,7 @@ describe('sign', (): void => {
 
   // since the libsecp256k1 signatures don't match (but can be verified), we
   // do both signing and verification here (checking the extracted key)
-  performanceWasm('secp256k1Sign', 1000, (_, onlyJs) =>
+  perfWasm('secp256k1Sign', 1000, (_, onlyJs) =>
     secp256k1Sign(msg, pair, undefined, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/secp256k1/verify.spec.ts b/packages/util-crypto/src/secp256k1/verify.spec.ts
index e01f919d6..4cc71f110 100644
--- a/packages/util-crypto/src/secp256k1/verify.spec.ts
+++ b/packages/util-crypto/src/secp256k1/verify.spec.ts
@@ -6,7 +6,7 @@ import '../bundleInit';
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { hasher } from './hasher';
 import { secp256k1PairFromSeed, secp256k1Verify } from '.';
 
@@ -63,7 +63,7 @@ describe('secp256k1Verify', (): void => {
     });
   });
 
-  performanceWasm('secp256k1Verify', 100, (_, onlyJs) =>
+  perfWasm('secp256k1Verify', 100, (_, onlyJs) =>
     secp256k1Verify(
       `\x19Ethereum Signed Message:\n${message.length.toString()}${message}`,
       '0x55bd020bdbbdc02de34e915effc9b18a99002f4c29f64e22e8dcbb69e722ea6c28e1bb53b9484063fbbfd205e49dcc1f620929f520c9c4c3695150f05a28f52a01',
diff --git a/packages/util-crypto/src/sha/asU8a256.spec.ts b/packages/util-crypto/src/sha/asU8a256.spec.ts
index e95c6a231..a369212a0 100644
--- a/packages/util-crypto/src/sha/asU8a256.spec.ts
+++ b/packages/util-crypto/src/sha/asU8a256.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { sha256AsU8a } from '.';
 
 const TESTS = [
@@ -43,7 +43,7 @@ describe('sha256AsU8a', (): void => {
     });
   });
 
-  performanceWasm('sha256AsU8a', 128000, (input, onlyJs) =>
+  perfWasm('sha256AsU8a', 128000, (input, onlyJs) =>
     sha256AsU8a(input, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/sha/asU8a512.spec.ts b/packages/util-crypto/src/sha/asU8a512.spec.ts
index 8913e7883..f14e62b36 100644
--- a/packages/util-crypto/src/sha/asU8a512.spec.ts
+++ b/packages/util-crypto/src/sha/asU8a512.spec.ts
@@ -3,7 +3,7 @@
 
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { sha512AsU8a } from '.';
 
 describe('sha512AsU8a', (): void => {
@@ -23,7 +23,7 @@ describe('sha512AsU8a', (): void => {
     });
   });
 
-  performanceWasm('sha512AsU8a', 64000, (input, onlyJs) =>
+  perfWasm('sha512AsU8a', 64000, (input, onlyJs) =>
     sha512AsU8a(input, onlyJs)
   );
 });
diff --git a/packages/util-crypto/src/test/index.ts b/packages/util-crypto/src/test/index.ts
new file mode 100644
index 000000000..b18e1f7c6
--- /dev/null
+++ b/packages/util-crypto/src/test/index.ts
@@ -0,0 +1,6 @@
+// Copyright 2017-2023 @polkadot/util-crypto authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+export { perf, perfCmp } from '@polkadot/util/test';
+
+export { perfWasm } from './performance';
diff --git a/packages/util-crypto/src/test/performance.ts b/packages/util-crypto/src/test/performance.ts
index 2783b74f6..f0765cd6d 100644
--- a/packages/util-crypto/src/test/performance.ts
+++ b/packages/util-crypto/src/test/performance.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { arrayRange } from '@polkadot/util';
-import { perf, perfCmp } from '@polkadot/util/test/performance';
+import { perf, perfCmp } from '@polkadot/util/test';
 
 import { randomAsU8a } from '..';
 
@@ -10,7 +10,7 @@ type ExecFn = (input: Uint8Array, onlyJs: boolean) => unknown;
 
 const GENERATED = arrayRange(256).map(() => [randomAsU8a()]);
 
-export function performanceWasm (name: string, count: number, exec: ExecFn, inputs = GENERATED): void {
+export function perfWasm (name: string, count: number, exec: ExecFn, inputs = GENERATED): void {
   perfCmp(name, ['WebAssembly', 'JavaScript'], count, inputs, exec);
 }
 
diff --git a/packages/util-crypto/src/xxhash/asU8a.spec.ts b/packages/util-crypto/src/xxhash/asU8a.spec.ts
index fbc7e05c1..2b9ba1deb 100644
--- a/packages/util-crypto/src/xxhash/asU8a.spec.ts
+++ b/packages/util-crypto/src/xxhash/asU8a.spec.ts
@@ -4,7 +4,7 @@
 import { hexToU8a } from '@polkadot/util';
 import { waitReady } from '@polkadot/wasm-crypto';
 
-import { performanceWasm } from '../test/performance';
+import { perfWasm } from '../test';
 import { xxhashAsU8a } from '.';
 
 describe('xxhashAsU8a', (): void => {
@@ -38,7 +38,7 @@ describe('xxhashAsU8a', (): void => {
     });
   });
 
-  performanceWasm('xxhashAsU8a', 8000, (input, onlyJs) =>
+  perfWasm('xxhashAsU8a', 8000, (input, onlyJs) =>
     xxhashAsU8a(input, 128, onlyJs)
   );
 });
diff --git a/packages/util/src/array/chunk.spec.ts b/packages/util/src/array/chunk.spec.ts
index 7ddf45556..54adc03e1 100644
--- a/packages/util/src/array/chunk.spec.ts
+++ b/packages/util/src/array/chunk.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { arrayChunk, arrayRange } from '.';
 
 describe('arrayChunk', (): void => {
diff --git a/packages/util/src/array/flatten.spec.ts b/packages/util/src/array/flatten.spec.ts
index 61db545eb..de578df16 100644
--- a/packages/util/src/array/flatten.spec.ts
+++ b/packages/util/src/array/flatten.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { arrayFlatten } from '.';
 
 const PERF_ONE = [[1, 2, 3, 4, 5]];
diff --git a/packages/util/src/array/shuffle.spec.ts b/packages/util/src/array/shuffle.spec.ts
index 8a60c520f..eaf6290ef 100644
--- a/packages/util/src/array/shuffle.spec.ts
+++ b/packages/util/src/array/shuffle.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { arrayRange, arrayShuffle } from '.';
 
 const ptest = arrayRange(16284);
diff --git a/packages/util/src/bi/toU8a.spec.ts b/packages/util/src/bi/toU8a.spec.ts
index cba4566c7..179171f81 100644
--- a/packages/util/src/bi/toU8a.spec.ts
+++ b/packages/util/src/bi/toU8a.spec.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { arrayRange } from '../array';
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { nToU8a } from '.';
 
 const ptest = arrayRange(65536).map((v) => [v]);
diff --git a/packages/util/src/bn/toU8a.spec.ts b/packages/util/src/bn/toU8a.spec.ts
index a46a6d1b5..bffa4be46 100644
--- a/packages/util/src/bn/toU8a.spec.ts
+++ b/packages/util/src/bn/toU8a.spec.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { arrayRange } from '../array';
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { BN, bnToU8a } from '.';
 
 const ptest = arrayRange(65536).map((v) => [v]);
diff --git a/packages/util/src/compact/fromU8a.spec.ts b/packages/util/src/compact/fromU8a.spec.ts
index f2b339f17..94076c6b8 100644
--- a/packages/util/src/compact/fromU8a.spec.ts
+++ b/packages/util/src/compact/fromU8a.spec.ts
@@ -3,7 +3,7 @@
 
 import { BN } from '../bn/bn';
 import { hexToU8a } from '../hex/toU8a';
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { compactFromU8a, compactFromU8aLim } from '.';
 
 describe('compactFromU8a', (): void => {
diff --git a/packages/util/src/hex/toU8a.spec.ts b/packages/util/src/hex/toU8a.spec.ts
index d9be141e4..b8c86aa28 100644
--- a/packages/util/src/hex/toU8a.spec.ts
+++ b/packages/util/src/hex/toU8a.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perfCmp } from '../test/performance';
+import { perfCmp } from '../test';
 import { hexToU8a as hexToU8aBuffer } from './toU8aBuffer';
 import { hexToU8a } from '.';
 
@@ -72,7 +72,7 @@ describe('hexToU8a', (): void => {
     ).toThrow(/hex value to convert/);
   });
 
-  perfCmp('hexToU8a', ['hexToU8aBuffer', 'hexToU8a'], 25, [[ptest]], (s: string, isSecond) =>
+  perfCmp('hexToU8a', ['hexToU8aBuffer', 'hexToU8a'], 40, [[ptest]], (s: string, isSecond) =>
     isSecond
       ? hexToU8a(s)
       : hexToU8aBuffer(s)
diff --git a/packages/util/src/hex/toU8a.ts b/packages/util/src/hex/toU8a.ts
index e07a94d50..e87d9a41a 100644
--- a/packages/util/src/hex/toU8a.ts
+++ b/packages/util/src/hex/toU8a.ts
@@ -4,8 +4,8 @@
 import type { HexString } from '../types';
 
 const CHR = '0123456789abcdef';
-const U8 = new Array<number>(256);
-const U16 = new Array<number>(256 * 256);
+const U8 = new Uint8Array(256);
+const U16 = new Uint8Array(256 * 256);
 
 for (let i = 0; i < CHR.length; i++) {
   U8[CHR[i].charCodeAt(0) | 0] = i | 0;
diff --git a/packages/util/src/is/ascii.spec.ts b/packages/util/src/is/ascii.spec.ts
index bcd2dd064..91f1855b3 100644
--- a/packages/util/src/is/ascii.spec.ts
+++ b/packages/util/src/is/ascii.spec.ts
@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { stringToU8a } from '../string';
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { isAscii } from '.';
 
 describe('isAscii', (): void => {
diff --git a/packages/util/src/is/codec.spec.ts b/packages/util/src/is/codec.spec.ts
index 92fb5a9a7..aaabfa776 100644
--- a/packages/util/src/is/codec.spec.ts
+++ b/packages/util/src/is/codec.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perfCmp } from '../test/performance';
+import { perfCmp } from '../test';
 import { isCodec } from '.';
 
 const ptest = {
diff --git a/packages/util/src/is/hex.spec.ts b/packages/util/src/is/hex.spec.ts
index 437f4c00f..e7f36e8e6 100644
--- a/packages/util/src/is/hex.spec.ts
+++ b/packages/util/src/is/hex.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { isHex } from '.';
 
 describe('isHex', (): void => {
diff --git a/packages/util/src/is/u8a.spec.ts b/packages/util/src/is/u8a.spec.ts
index 85e63407d..09ebd56a3 100644
--- a/packages/util/src/is/u8a.spec.ts
+++ b/packages/util/src/is/u8a.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { isU8a } from '.';
 
 describe('isU8a', (): void => {
diff --git a/packages/util/src/is/undefined.spec.ts b/packages/util/src/is/undefined.spec.ts
index 13a962cb3..0e14496ee 100644
--- a/packages/util/src/is/undefined.spec.ts
+++ b/packages/util/src/is/undefined.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { isUndefined } from '.';
 
 describe('isUndefined', (): void => {
diff --git a/packages/util/src/object/property.spec.ts b/packages/util/src/object/property.spec.ts
index cd74a80d7..11f546bdc 100644
--- a/packages/util/src/object/property.spec.ts
+++ b/packages/util/src/object/property.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { objectProperties, objectProperty } from '.';
 
 describe('objectProperty/objectProperties', (): void => {
diff --git a/packages/util/src/object/spread.spec.ts b/packages/util/src/object/spread.spec.ts
index 0c318448d..ea46884a2 100644
--- a/packages/util/src/object/spread.spec.ts
+++ b/packages/util/src/object/spread.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { objectSpread } from '.';
 
 describe('objectSpread', (): void => {
diff --git a/packages/util/src/string/camelCase.spec.ts b/packages/util/src/string/camelCase.spec.ts
index 4287c8d19..6d49231f2 100644
--- a/packages/util/src/string/camelCase.spec.ts
+++ b/packages/util/src/string/camelCase.spec.ts
@@ -4,7 +4,7 @@
 import { getRandomValues } from '@polkadot/x-randomvalues';
 
 import { arrayRange } from '../array';
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { stringCamelCase, stringUpperFirst } from '.';
 
 const SEPS = [' ', '_', '-', '.', ','];
diff --git a/packages/util/src/string/lowerFirst.spec.ts b/packages/util/src/string/lowerFirst.spec.ts
index e8ba94a0e..9bb1d8cb9 100644
--- a/packages/util/src/string/lowerFirst.spec.ts
+++ b/packages/util/src/string/lowerFirst.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { stringLowerFirst } from '.';
 
 describe('stringLowerFirst', (): void => {
diff --git a/packages/util/src/string/upperFirst.spec.ts b/packages/util/src/string/upperFirst.spec.ts
index f26fff2e2..22ad3fc8e 100644
--- a/packages/util/src/string/upperFirst.spec.ts
+++ b/packages/util/src/string/upperFirst.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { stringUpperFirst } from '.';
 
 describe('stringUpperFirst', (): void => {
diff --git a/packages/util/src/test/index.ts b/packages/util/src/test/index.ts
new file mode 100644
index 000000000..0ad5e889c
--- /dev/null
+++ b/packages/util/src/test/index.ts
@@ -0,0 +1,4 @@
+// Copyright 2017-2023 @polkadot/util authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+export { perf, perfCmp } from './performance';
diff --git a/packages/util/src/u8a/cmp.spec.ts b/packages/util/src/u8a/cmp.spec.ts
index 56979f0f5..eef7e0eec 100644
--- a/packages/util/src/u8a/cmp.spec.ts
+++ b/packages/util/src/u8a/cmp.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aCmp } from '.';
 
 const ltest = new Uint8Array(32768);
diff --git a/packages/util/src/u8a/concat.spec.ts b/packages/util/src/u8a/concat.spec.ts
index 90529fd7a..cfde8ab41 100644
--- a/packages/util/src/u8a/concat.spec.ts
+++ b/packages/util/src/u8a/concat.spec.ts
@@ -4,7 +4,7 @@
 import { getRandomValues } from '@polkadot/x-randomvalues';
 
 import { arrayRange } from '../array';
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aConcat, u8aConcatStrict } from '.';
 
 const ptest = arrayRange(10).map(() => getRandomValues(new Uint8Array(32)));
diff --git a/packages/util/src/u8a/empty.spec.ts b/packages/util/src/u8a/empty.spec.ts
index 5812a7e08..e76371557 100644
--- a/packages/util/src/u8a/empty.spec.ts
+++ b/packages/util/src/u8a/empty.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aEmpty } from '.';
 
 describe('u8aEmpty', (): void => {
diff --git a/packages/util/src/u8a/eq.spec.ts b/packages/util/src/u8a/eq.spec.ts
index 17e4eefbc..9fa0b309b 100644
--- a/packages/util/src/u8a/eq.spec.ts
+++ b/packages/util/src/u8a/eq.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aEq } from '.';
 
 const ltest = new Uint8Array(32768);
diff --git a/packages/util/src/u8a/toBigInt.spec.ts b/packages/util/src/u8a/toBigInt.spec.ts
index c4ca3e5a8..b43a1d12f 100644
--- a/packages/util/src/u8a/toBigInt.spec.ts
+++ b/packages/util/src/u8a/toBigInt.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aToBigInt } from '.';
 
 describe('u8aToBigInt', (): void => {
diff --git a/packages/util/src/u8a/toBn.spec.ts b/packages/util/src/u8a/toBn.spec.ts
index 517a89bef..deaa839be 100644
--- a/packages/util/src/u8a/toBn.spec.ts
+++ b/packages/util/src/u8a/toBn.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aToBn } from '.';
 
 describe('u8aToBn', (): void => {
diff --git a/packages/util/src/u8a/toHex.spec.ts b/packages/util/src/u8a/toHex.spec.ts
index 618b8290f..c8aad80cd 100644
--- a/packages/util/src/u8a/toHex.spec.ts
+++ b/packages/util/src/u8a/toHex.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perfCmp } from '../test/performance';
+import { perfCmp } from '../test';
 import { u8aToHex as u8aToHexBuffer } from './toHexBuffer';
 import { u8aToHex } from '.';
 
diff --git a/packages/util/src/u8a/toNumber.spec.ts b/packages/util/src/u8a/toNumber.spec.ts
index d6b626dfc..c5d48ebb8 100644
--- a/packages/util/src/u8a/toNumber.spec.ts
+++ b/packages/util/src/u8a/toNumber.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aToNumber } from '.';
 
 describe('u8aToNumber', (): void => {
diff --git a/packages/util/src/u8a/toU8a.spec.ts b/packages/util/src/u8a/toU8a.spec.ts
index 30bf59c0d..6861a6b01 100644
--- a/packages/util/src/u8a/toU8a.spec.ts
+++ b/packages/util/src/u8a/toU8a.spec.ts
@@ -1,7 +1,7 @@
 // Copyright 2017-2023 @polkadot/util authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
-import { perf } from '../test/performance';
+import { perf } from '../test';
 import { u8aToU8a } from '.';
 
 describe('u8aToU8a', (): void => {
diff --git a/packages/x-randomvalues/package.json b/packages/x-randomvalues/package.json
index cc9c732fb..36e10a99b 100644
--- a/packages/x-randomvalues/package.json
+++ b/packages/x-randomvalues/package.json
@@ -26,6 +26,7 @@
     "@polkadot/x-global": "10.2.7-7-x"
   },
   "devDependencies": {
+    "@polkadot/util": "10.2.7-7-x",
     "@types/react-native": "^0.71.0"
   },
   "denoDependencies": {
diff --git a/packages/x-randomvalues/src/base64.spec.ts b/packages/x-randomvalues/src/base64.spec.ts
index 14bb69fe8..7c86fcb3c 100644
--- a/packages/x-randomvalues/src/base64.spec.ts
+++ b/packages/x-randomvalues/src/base64.spec.ts
@@ -1,12 +1,16 @@
 // Copyright 2017-2023 @polkadot/util-crypto authors & contributors
 // SPDX-License-Identifier: Apache-2.0
 
+import { perf } from '@polkadot/util/test';
+
 import { base64Decode } from './base64';
 
+const HELLO_DUAL = 'aGVsbG8gd29ybGQg0J/RgNC40LLQtdGC0YHRgtCy0YPRjiDQvNC4IOS9oOWlvQ==';
+
 const TESTS = [
   {
     // hello world Приветствую ми 你好
-    base64: 'aGVsbG8gd29ybGQg0J/RgNC40LLQtdGC0YHRgtCy0YPRjiDQvNC4IOS9oOWlvQ==',
+    base64: HELLO_DUAL,
     expect: new Uint8Array([104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100, 32, 208, 159, 209, 128, 208, 184, 208, 178, 208, 181, 209, 130, 209, 129, 209, 130, 208, 178, 209, 131, 209, 142, 32, 208, 188, 208, 184, 32, 228, 189, 160, 229, 165, 189])
   },
   {
@@ -40,3 +44,5 @@ describe('base64Decode', (): void => {
     ).toEqual(test.expect);
   });
 });
+
+perf('base64Decode (hello, dual)', 100_000, [[HELLO_DUAL]], base64Decode);
diff --git a/packages/x-randomvalues/src/base64.ts b/packages/x-randomvalues/src/base64.ts
index a2f6fc4a2..99fbc0b51 100644
--- a/packages/x-randomvalues/src/base64.ts
+++ b/packages/x-randomvalues/src/base64.ts
@@ -9,6 +9,14 @@
 // We provide an own (tiny) decoder to not have Buffer deps
 
 const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
+const map = new Uint8Array(256);
+
+// We use charCodeAt for access here and in the decoder loop - this is faster
+// on lookups (array + numbers) and also faster than accessing the specific
+// character via data[i] (around a 50% improvement on perf tests)
+for (let i = 0; i < chars.length; i++) {
+  map[chars.charCodeAt(i)] = i;
+}
 
 export function base64Decode (data: string): Uint8Array {
   const bytes = [];
@@ -17,7 +25,7 @@ export function base64Decode (data: string): Uint8Array {
 
   for (let i = 0; i < data.length && data[i] !== '='; i++) {
     // each character represents 6 bits
-    byte = (byte << 6) | chars.indexOf(data[i]);
+    byte = (byte << 6) | map[data.charCodeAt(i)];
 
     // each byte needs to contain 8 bits
     if ((bits += 6) >= 8) {
diff --git a/packages/x-randomvalues/tsconfig.build.json b/packages/x-randomvalues/tsconfig.build.json
index 9f4369850..1d856f796 100644
--- a/packages/x-randomvalues/tsconfig.build.json
+++ b/packages/x-randomvalues/tsconfig.build.json
@@ -5,6 +5,9 @@
     "outDir": "./build",
     "rootDir": "./src"
   },
+  "exclude": [
+    "**/*.spec.ts"
+  ],
   "references": [
     { "path": "../x-global/tsconfig.build.json" }
   ]
diff --git a/packages/x-randomvalues/tsconfig.spec.json b/packages/x-randomvalues/tsconfig.spec.json
new file mode 100644
index 000000000..8d5886f77
--- /dev/null
+++ b/packages/x-randomvalues/tsconfig.spec.json
@@ -0,0 +1,18 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "baseUrl": "..",
+    "outDir": "./build",
+    "rootDir": "./src",
+    "resolveJsonModule": true,
+    "emitDeclarationOnly": false,
+    "noEmit": true
+  },
+  "include": [
+    "**/*.spec.ts"
+  ],
+  "references": [
+    { "path": "../util/tsconfig.build.json" },
+    { "path": "../x-global/tsconfig.build.json" }
+  ]
+}
diff --git a/tsconfig.build.json b/tsconfig.build.json
index 75ddc8c06..40cec2bbd 100644
--- a/tsconfig.build.json
+++ b/tsconfig.build.json
@@ -15,6 +15,7 @@
     { "path": "./packages/x-fetch/tsconfig.build.json" },
     { "path": "./packages/x-global/tsconfig.build.json" },
     { "path": "./packages/x-randomvalues/tsconfig.build.json" },
+    { "path": "./packages/x-randomvalues/tsconfig.spec.json" },
     { "path": "./packages/x-textdecoder/tsconfig.build.json" },
     { "path": "./packages/x-textencoder/tsconfig.build.json" },
     { "path": "./packages/x-ws/tsconfig.build.json" }
diff --git a/yarn.lock b/yarn.lock
index 3b384d00d..6f067bdb3 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2411,6 +2411,7 @@ __metadata:
   resolution: "@polkadot/x-randomvalues@workspace:packages/x-randomvalues"
   dependencies:
     "@babel/runtime": ^7.20.13
+    "@polkadot/util": 10.2.7-7-x
     "@polkadot/x-global": 10.2.7-7-x
     "@types/react-native": ^0.71.0
   languageName: unknown