Christian,
I have used 2 video cards with no problems as of yet. Of
the AGP type I have used a Matrox G200 with 16 meg and PCI
wise, I have used a Diamond Viper 550 16 meg without issues.
More important though, is your hard drive. Try one of the
new 7200 rpm or a Seagate 10,000 rpm drive. That cleared up
all my pop and click issues.
Doug