Graphics card or PSU or Mother board?

[ColdCase]

I have a rev B (Jan 2008) Mac Pro

Two 2.8GHz Quad-Core Intel Xeo
~16GB RAM
NVIDIA GeForce 8800 GT 512MB
4x 750GB 7200-rpm Serial ATA
One 256 GB SSD in optical drive bay
One 16x SuperDrive
AirPort Extreme Card (Wi-Fi)
eSATA adapter card
USB adapter card

After years of trouble free use, I started getting random shut downs.

I am now getting screen flickers and video artifacts (as if the screen is a square piece jigsaw puzzle with mixed up pieces) and other strange behavior and color aberations. I have been able to reboot and operate normally for hours but the display problems sometimes start on cold boot now.

I opened up the cover and found very little dust, but vacuumed anyway.

There are no red fault lights anywhere I can see.

Wiggling the display connector or switching display ports sometimes improves but does not eliminate video artifacts.

Before I start replacing parts, does this sound most likely a video card issue or a power supply problem?

I did a search and uncovered a bunch of useful information, but the video card problems all seemed to be blank screens.

I have been using Macs since the 80s, but this MacPro has been so trouble free that I haven't been keeping track of the common issues.

Thanks

Oh its at OS 10.6.8

 

[DoFoT9]

The artifacting hints at GPU, any glitches of that sort more or less are. And the 8800 wasn't exactly the most stable of cards!!

The random shut downs though... Could be PSU OR motherboard!!

Do you have another GPU to test with? I'm guessing not

 

[MacVidCards]

try safe boot

if it clears up artifacts then it is mos likely 8800GT

preheat oven to 425F and google "bake nvidia 8800"

you will need a small phillips to remove fan

 

[ColdCase]

try safe boot

I forgot to mention that I did try safe boot and artifacts remained (screen is fine for a few minutes but slowly degrades). I also ran disk repair/repair permissions on all the drives.


I really don't have any spare parts about.

Oh and some of those baking posts look similar to some of the artifacts I was seeing.

 

[DoFoT9]

Then it seems quite likely that the GPU is the cause of the issues..

 

[ColdCase]

Solved

Just to close out this thread in case others find it.

I picked up a RADEON HD 5870 upgrade kit from Apple and the machine is now happy. No random shut down, no random disk activity, and no video artifacts.

I know the card is overpriced from Apple, but better with education store discounts and there is no fuss. I didn't want to deal with one of my video or graphics application not dealing well with a flashed graphics card. The 5870 just works, hopefully for awhile.

I'm going to try baking the faulty 8800 at some point.

 

[chiefroastbeef]

Just to close out this thread in case others find it.

I picked up a RADEON HD 5870 upgrade kit from Apple and the machine is now happy. No random shut down, no random disk activity, and no video artifacts.

I know the card is overpriced from Apple, but better with education store discounts and there is no fuss. I didn't want to deal with one of my video or graphics application not dealing well with a flashed graphics card. The 5870 just works, hopefully for awhile.

I'm going to try baking the faulty 8800 at some point.

Glad to hear! Please update us on your gpu baking experience.