nvidia GeForce FX 5200 problem

Hello, I have problem with nvidia GeForce FX 5200 graphics card on Suse 9.1 64bit. When some specific output should be displayed (mostly scrolling in xterm/Mozilla etc.), display is switched to black for 1 second. It's like blank screen saver, but I'm pretty sure that it's not misconfigured screen saver :-) I have tried both 1.0-5332 and 1.0.6106 drivers, I have tried Option "AGPMode" "4" or Option "NvAgp" "1", but nothing has changed. The problem is both with kernels 2.6.5-7.75 and 2.6.5-7.95. Has anyone else the same problem? Mirek Ruda