@eyalamir yes in release mode. Perhaps the issue that I’m using 1024 (256 *4) samples length. As far I know accelerate framework from Apple can handle 16 samples.
A similar issue was discussed in this thread - No performance improvement with FloatVectorOperations
Test Devices:
iPad 12.9 inch A12X
MacBook m1 (10-15% less load)
-ffast-math
-Ofast
-flto