Needless to say, the first thing you should do is to make sure that your BIOS program, motherboard chipset (VIA chipset owners, take note!), video and sound cards drivers are up to date.
Some people are reporting that they have resolved this problem by changing a BIOS setting or two, resulting in no noticeable decrease in performance in OFP or any other software.
In the BIOS program, under 'Advanced Chipset Features' (or something similar) try reducing the AGP aperture setting or similar to 64Mb. If that alone doesn't work, there is a setting called 'AGP-4x Mode' or something similar. Try disabling this BIOS option and see if that resolves the problem.
(Thanks to Roland Gerschwarzenge and others for this entry).
Another thing to check out is if your computer's motherboard is based on the VIA chipset, read this FAQ item.
Overclocking anything on your PC? Then read this.
If none of the above has resolved your problem and you're up the creek without a paddle, follow these instructions for contacting BIS support directly.