Viper V770 and AGP Aperture Size

[Sarevok]

I replaced a Viper V550 16mb video card (which was working ok with w98) with a V770 32mb card and whenever it booted up halfway to windows I would get a windows protection error and the system would say hit enter to reset. The AGP Aperture size was set to 256mb in the BIOS and worked OK with the V550 16mb. I changed it to 128mb with the V770 and now the system boots up ok and windows runs fine. What gives? What does this aperture setting do and why will it not run the V770 at 256mb but will run the V550? Thanks

[LordLocksley]

The standard aperture size is usually double the memory on the card. From my understanding (I could be wrong) the aperture is the max. ammount of system memory the card can use similar to virtual memory.
Hope this helps.