2008 Mac Pro and PowerColor ATI Fanless HD6850 SCS3

[Nutcasey]

Hello!

I have a Mac Pro from 2008 as shown below and bought the following graphics card for it:

6850

I put it into the number 2 16x PCI-E slot and it managed to stay on for about 5 minutes before the whole computer turned itself off. A red light then turned on near the RAM on the motherboard. I thought this Mac would have enough power to handle this card. Does anyone know what might be wrong with it? Any help would be great.

  Model Name:	Mac Pro
  Model Identifier:	        MacPro3,1
  Processor Name:	        Quad-Core Intel Xeon
  Processor Speed:	        2.8 GHz
  Number of Processors:	        2
  Total Number of Cores:	8
  L2 Cache (per Processor):	12 MB
  Memory:	                6 GB
  Bus Speed:	                1.6 GHz
  Boot ROM Version:	        MP31.006C.B05
  SMC Version (system):	        1.25f4

 

[ashman70]

How many power connectors were plugged into the video card?

 

[Nutcasey]

I plugged in the one connector that the card seemed to require. This was the same connector that used to be plugged into my old stock nvidia card that came with the machine.

 

[Nutcasey]

Here is my system info with and without the new ATI card if it helps. I tried a different power cable on the mother board but that didn't seem to change anything. The whole thing just starts to shut down after about 10 minutes of use.

 

[mrgreen4242]

If it runs for awhile and shuts down, it sounds like a heat issue, and you mentioned it was fanless...maybe try manually ramping up the fan speeds in the case temporarily to test it. If that works, return it for a card with a fan.