Hashrate very low on CPU - Win10 > Linux

I have been mining on my CPU when I used Windows 10 and I was getting ~570H/s mining CryptonightV7

I have since moved over to Linux and I am only getting around 300H/s at very best.

I am wondering why this could be.
Ubuntu 18.04 - Stock Kernel
AMD Ryzen 1600 @ 3.7Ghz
UEFI has CB15 Bias enabled

Was the miner compiled with a different compiler? Were the same flags used?

Previously I was using NiceHash on Windows, so just an .exe

Any more assistance?
I haven’t been able to get the increase

as @pFtpr was hinting at, just rebuild, … or try the same .exe on linux through wine.