Found the probable reason this has lower scores than the EWBF miner. Turns out it does not trigger 3D mode on your card, which disables OC and Boost.
You can replicate that by running Media Player Classic in Enhanced Video Renderer mode and even minimizing the paused video.
I got between 30 and 50 extra Sol/s
Yeah, that's why I have to run Chrome to get maximum speed. It somehow triggers 3D mode, which triggers nVidia Boost mode and apply all additional overclockings. Before I thought it is problem of my card or Gainward ExpertTool software, but today I installed new PC with my new EVGA GTX 1070 Ti, fresh Windows 10, latest drivers, latest DSTM, MSI Afterburner used for overclocking and yet even here I have to run Chrome to get maximum speed. Without Chrome I'm getting 450 Sol/s, with Chrome running, I can get up to 540 Sol/s (card is overclocked of course).