A few months ago I decided to take the plunge and upgrade my ageing 2006 Mac Pro to a new model. After much research it seemed the 6 core model was the way to go (and much of the time, actually faster than the 8 core and 12 core models). My initial concern of having only 16GB of RAM vanished with OWC started selling 24GB and 32GB kits. (I have a 24GB in mine).
All was working well, the machine is QUICK! (especially with an SSD for applications and OS). However one day upon sitting down in front of the computer, the displays would not turn on. (I have 2×24″ Dells and a 1×27″ Dell attached).
I did the normal thing, check the connections, restart etc. I noticed that despite no display the machine still seemed to be working. I tried remoting in via screen-sharing from my Macbook Pro which worked. So the system was fine, the GPU was being weird. After many restarts, resetting PRAM, all the standard trouble shooting things I gave up and called AppleCare.
The graphics card was no longer showing up under machine information, which I figured meant a dead card. The folks at AppleCare agreed and gave me the number of a repair company to come out. This was late Friday and the repair couldn’t be organised until the following week. Over the weekend, just for kicks I decided to re-seat the GPU as this had somehow fixed a RAM issue I had once. I pulled the power out of the card (2 of them) and halfway through figured it wasn’t worth the effort. I plugged it back in, turned it on so I could get some data off the machine to my Macbook Pro, and my screens suddenly sprung to life.
I’m not exactly sure what happened, but disconnecting the power to the card seemed to do something. I canceled the AppleCare repair and went about my daily life.
1 month later I had the same issue, no display. I did the same thing (pull the power on the card) and it worked. I have no idea why, but it seems Apple struggles to make a reliable graphics card. I had two fail in my 2006 Mac Pro.
The card is now working fine, but I’m worried about the next time this happens. There is no way to pinpoint what is going on, and as any tech person knows these are the most frustrating and time consuming issues to fix.
So, I have no real solution if anyone out there has the same problem, but try the power thing, it might get you up and going again in a crisis 🙂