NVIDIA GeForce 8800 GTproblems in my 2008 mac pro

Just had this problem this morning with my Mac Pro...was web browsing when suddenly I had wavy blue lines of pixels across both my displays and, even though I could move my cursor, the machine was unresponsive.

I held the power button down to shut it down and restarted it; on the boot screen the wavy lines were still there but more faint than at first but the spinner below the Apple logo stopped and the machine wouldn't boot.

I tried again in Safe Mode and got the progress bar at the bottom of the screen (still covered in faint, blue, wavy lines) and it filled about a third of the way before disappearing. Several seconds later the spinner stopped and the machine still won't boot.

When I get home this afternoon I'm going to try the dusting solution--hopefully I have as much success.

Run SmcFanControl @ 900 rpm will help air flow and heat, especially important for 2008 and earlier model.

I run SmcFanControl on my '06 Mac Pro (which is a replacement for one that burned up when I WASN'T using SmcFanControl--ruined the logic board and both processors), but never had any issues with my 8-core machine...until this morning. I'll give the dusting and software solution a shot and report back here.

In the meantime, here's what I'm seeing:

This is a shot of the spinner stopped on startup with the wavy lines that preceeded my non-booting still visible...

I picked up a little dust devil that was recommended many times for use with and around computers and other places -

http://www.amazon.com/gp/product/B001J4ZOAW/

8800GTs solder joint issue?

https://discussions.apple.com/thread/3650799?answerId=18165544022#18165544022

Baking A Video Card - Nvidia 8800 GT (AKA Reflow) - YouTube

Baking your 8800gtx main board - Nvidia - Graphic-Displays

Broken Graphic Card?? BAKE IT!!! - YouTube

Well, gang, it's definitely my graphics card. I'm writing this via screen sharing through my MacBook Pro into my graphically-incapable Mac Pro.

Blowing out the dust on the card didn't do the trick and there was little-to-no dust anywhere else in the machine. And I wasn't positive off the top of my head that my card was an 8800GT, but I confirmed it after remoting in. The baking trick looks interesting! I might give it a try after I have a replacement in hand just to have the failed unit around as a spare, but I have to much work to do to rely on a DYI repair like that as a primary.

Thanks for the info, Hatter! And Franzleojames, I hope you have better luck with your 8800 in the future.

And a side note for anyone who wasn't sure but was interested like I was: plugging in a spare Radeon X1900 XT from a quad-core Mac Pro didn't work on my 8-core machine. It didn't like the X1900 any better than it did the dead 8800GT... Eh, figured it was worth a shot... 🙂

I had the same problem. Please see this discussion. https://discussions.apple.com/thread/3854622?answerId=18158931022#18158931022

The baking trick worked for me. Apparently what happens is that it remelts and resets the solder, thereby filling in cracks which may have developed.

I am not in the least bit techy, so I did a lot of research, videos on Youtube, etc. One thing I had to do which does not seem to be mentioned much is to renew the thermal paste on the processor (a tiny spot is all that is required). Thermal paste improves conductivity from the processor to the heat sink and thereby helps with the dissipation of heat. It is very cheap to purchase.

So far my MacPro is working fine. If it goes again I will buy a new card.

I don't see the point in waiting until you have a new card. If you need a new card then just go ahead and get one and forget about baking. It will probably outlast your MacPro. You might as well try the baking trick and run with it as long as it works, then get a new card. It might run for a few years, or it might fail almost immediately, but you will be no worse off than you are today if that happens.

One advantage of the baking trick is that it has forced me to get a better knowledge of the inside of my computer, and I now feel more confident about doing upgrades etc.

Good luck with whatever choice you make.