Hi Since upgrading to Snow Leopard, I'm having this weird mouse skipping/jumping problem. Here it goes: I have two monitors plugged in to the video card at all times. If the second display is on (power on), mouse works just fine. However, if I turn off this second monitor, I'll get repeating jumps on the mouse. Every 5 to 7 seconds the cursor will stop for a whole second, even if I keep moving the mouse, then it will jump to a distant place in the screen. Then I turn back on the second display, and mouse goes back to normal. I got a 1.1 mac pro with a flashed ati video card. I don't know if this problem is due to upgrading to snow leopard or from installing a flashed card. Thanks!