8800GT related crashes?

[badlydrawn]

Hi guys,

I have a somewhat worrying occurance here since today morning, where during surfing with Safari, my whole system would lockup completely! This never happened to me before. I recently upgraded (last Friday) to an 8800GT on my 2006 Mac Pro. Checking the Console I get these messages:

1/5/08 2:31:03 PM kernel NVChannel(GL): Graphics channel timeout! 
1/5/08 2:31:15 PM kernel NVChannel(GL): Graphics channel timeout! 
1/5/08 2:31:27 PM kernel NVChannel(GL): Graphics channel timeout! 
1/5/08 2:31:27 PM kernel NVChannel(GL): Graphics channel exception!  status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error 
1/5/08 2:31:27 PM kernel 0000000b 
1/5/08 2:31:30 PM ntpd[591] time reset -0.313233 s 
1/5/08 2:31:38 PM kernel NVChannel(GL): Graphics channel timeout! 
1/5/08 2:31:38 PM kernel NVChannel(GL): Graphics channel exception!  status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error 
1/5/08 2:31:38 PM kernel 0000000b 
1/5/08 2:31:38 PM kernel NVChannel(GL): Graphics channel exception!  status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error 
1/5/08 2:31:38 PM kernel 0000000b 
1/5/08 2:31:50 PM kernel 2 = 0x3 = Fifo: Unknown Method Error 
1/5/08 2:31:50 PM kernel 0000000b 
1/5/08 2:31:50 PM kernel NVChannel(GL): Graphics channel exception!  status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error 
1/5/08 2:31:50 PM kernel 0000000b 
1/5/08 2:32:02 PM kernel NVChannel(GL): Graphics channel timeout! 
1/5/08 2:32:02 PM kernel NVChannel(GL): Graphics channel exception!  status = 0xffff info32 = 0x3 = Fifo: Unknown Method Error 
1/5/08 2:32:02 PM kernel 0000000b 
1/5/08 2:32:14 PM kernel NVChannel(GL): Graphics channel timeout!

Does anyone know what could be going wrong here? I had just starting up the system, and haven't had any issues yesterday before shutting down.

TIA.
badlydrawn.