> which means that not even writing C++ SIMD code will make me have a faster implementation than the one Python is using and I will probably have to write my ow

> which means that not even writing C++ SIMD code will make me have a faster implementation than the one Python is using and I will probably have to write my own assembly code I believe assembly is almost always the wrong choice in modern world. It’s just that your SIMD version is not very efficient. Your original SIMD version completes in 0.065ms on my computer. Here’s an optimized version which completes in 0.038ms i.e. 1.7x faster: https://gist.github.com/Const-me/41b013229b20f920bcee22a856c8569f https://gist.github.com/Const-me/41b013229b20f920bcee22a856c... Note I have used 4 sets of the accumulators to workaround relatively high latency of the FMA instructions. However, I’m pretty sure the implementation used by these Python libraries is leveraging multiple CPU cores under the hood. Here’s another C++ version which does that as well, it completed in 0.0136 ms on my computer i.e. 4.8x faster: https://gist.github.com/Const-me/c61e836bed08cef2f06783c7b11b4e18 https://gist.github.com/Const-me/c61e836bed08cef2f06783c7b11...