I recently purchased a geforce 5700 personal cinema video card, which is an 8x AGP. My motherboard can only handle 4x, but I was assured that my video card would run at 4, as well as 8. I installed the card, disabled the onboard video in my BIOS, turned the machine off, hooked the monitor to the new card, and restarted. I was given the beep code for display memory read/write failure (8 beeps, on an amibios), and my monitor went into standby mode. I was forced to clear the cmos to restore my display. I then borrowed an ATI Radeon 9250, which outright states it can run at 4x/8x. I proceeded as before, installing the card, disabling onboard video, shutting down, connecting the monitor, and restarting. I had the same result of the 8 beeps and the standby mode. I borrowed a PCI video card (an ancient mach64) just to test if my machine would boot running that, and it did, after disabling the onboard video. I've heard there might be issues with the power supply (350 watts, but used and fairly cheap), but the fact that it runs fine with the PCI card leads me to think otherwise. Does anyone have any idea what the issue might be?