I have spent the weekend trying to set up Unirefresh/Vbehz on my Retro-PC in order to achieve more than 60hz refresh rate in DOS-games for my CRT-monitor.

Brief details of my setup:

QDI Advance 10T S370 (Via 694T chipset)
P3-S 1400MHz
512MB RAM
Geforce Ti 4400
AWE64+SB Audigy
etc etc

Setting up both Unirefresh and Vbehz works without issues so i have no trouble to get desired refresh rate in VESA resolutions (mainly using 640x480) under MS-DOS. However when refresh rate is set anything else than default 60Hz I receive flashing "artifacts" in the image on most of my tested games, for example Duke 3D, Blood, KKND etc. In Duke 3D i can clearly see the status bar from the game in the flashes by but with incorrect allignment. The frequency of the flashes varies, from every 2-3 seconds to not being seen in a couple of minutes. It seems Unirefresh gives slightly less artifacts compared to Vbehz. I have no other issues with this computer.

I tried swapping the graphics card to a Geforce 4MX 440 and it seems it improved a bit. Also it seems disabling AGP 4X might have improved slightly, but not sure.

Anyone else has experienced this? I am trying to figure out if this is caused by the video card or the motherboard or a combination of both (I doubt it has to do with the monitor, but you never know).