I found this: http://c0d3rmod.blogspot.com/

"domingo, 31 de dezembro de 2017
XMR-Stak modified version with improvements in hash rate and zero dev fee.
Tested under AMD Radeon RX Vega 64, average H/S: 2145
https://www.4shared.com/zip/KFpGrwY7ei/xmr-stak_c0d3r-mod.html
https://www.sendspace.com/file/qvnnui
For coins based on cryptonote like Monero, Electroneum and others."

I found it because it was mentioned there: http://monerobenchmarks.info/
AMD RADEON RX VEGA 64 [2016+1600]   8 GB HBM2 MEMORY   2145   N/A   XMR-STAK [C0D3R MOD]   WINDOWS 10 x64   Dec, 2017

With Standart XMR-STAK and Gigabyte VEGA 64 GAMING OC 8G  i got 1925H/s per card, used following guide:  (https://www.reddit.com/r/MoneroMining/comments/74hjqn/monero_and_vega_the_definitive_guide/)

Will try this modified version later, will it improve H/s..