Had to install Windows 7 x86 on the old PC with SiS650-based motherboard. The 315 IGP is detected by Windows 7 as “Standard VGA Graphics Adapter”. With 800×600 resolution everything was working fine but when I tried to switch to 1280×1024 mode the LCD monitor went dark and showed “not recommended mode” sign. From monitor info menu I found out what graphics adapter had set the refresh rate to 87Hz and monitor wanted 60Hz.

It seems what for “Standard VGA Graphics Adapter” Windows 7 does not allow you to change the refresh rate, showing only “Hardware Default”. The graphics adapter uses the refresh rates from its VESA BIOS. I guessed what the adapter was not reading or using the monitor DDC information. Luckily on Wim’s BIOS page I found the patched BIOS for this motherboard where the Video BIOS was replaced with newer version. Flashing this BIOS solved the refresh rate issue.