Thank you so much for your help. I apologize but am a total newbie...
In the BIOS screen i have the following entries:
CPU Multiplier [9.5]
FSB - Memory Clock Mode [Linked]
FSB - Memory Ratio [Auto] FSB QDR, MHz  <----- I suppose I have to change THIS value, right? so if I put 1700 (425x4) the system doesn't start and after a reboot I have the message that BIOS has falied...
What am I doing wrong?
About the quad, thanks for the suggestion but I have found on many forums and magazines that MS FSX doesn't get any advantage by neither the quad nor by SLI. Do you think different?