When i installed the graphics card in a somewhat modern Core2Duo system, everything went fine. When i wrote the Memory range settings (obtained from new system) to the PCI registers of the graphics card using a DOS based PCI config utility in my old system, i was able to use the same in Windows XP but with poor performance.
i decided to disassemble my mainboard bios to understand the incompatibility and possibly mod the bios for proper detection. one abnormality i noticed was that my motherboard(award ver 6.00) bios doesn't not properly identify device BAR's if it is a combination of 'Prefetchable' type and '64 bit decoder' while pci enumeration. it is handling prefetchable memory requests(64-bit memory space) by the pci devices as 'non-prefetchable' which is the default when there is no match with the last 4 bits of BAR.
can someone shed some light on the consequences, if a non-prefetchable address range is assigned by the host to the 'prefetchable' type BAR of a pci device. i just want to know whether this is the main culprit so that i can attempt to mod my bios or it is inconseequential.