Genneraly run the memmory at the speed of your simm, if overclocking setting the simm speed to a slower rate than what the simm is marked for might be needed. I imagine this isn't an overclocked unit so set that aside.
When I had a BPPC040 in my system together with a 3.5" HD and an external floppydrive powered by an 250W PSU the mouse sprite wuold become more and more jumpy as the CPU intensityload got higher... didn't catch the problem untill a few days later when my harddrive actualy spun down and up again freezing my computer when I accessed both floppys at the same time (doing an XCopy)! The Issue was a loss of power over the powercord to the computer and after adding another input of power to the motherboard (using one of the existing molex) all problem was solved.
So try add more power to the motherboard though another input. Now I did this by soldering a female molex to the same place on the motherboard as the powercord eneter but you could probably do a less intrusive operation using the floppypower connector as you "input point".
