2008 iMac Continuing Issues

I'm in the same boat. iMac 8.1 3.06 8800gs. Apple is a marketing machine now and it's all about the bottom line so I would suggest licking your wounds and build something to last.

They didn't create the OS themselves, and the hardware is now Intel based so there really is nothing special anymore except smooth metal and shiny screens.

I bought a refurbished 8800gs and have mine on ebay. Why do you think there are so many reburbs for sale?

These aren't the Macs of old.

this may well be a dumb question, but will other MXM PCI Express graphics cards work? Or would they require flashing/mac drivers?

For anyone with a failing GPU in an iMac made before 2009 that can't get any help and doesn't want to pay to replace the GPU should probably try the bake technique.

http://www.sec.gov/Archives/edgar/data/1045810/000119312508145974/d8k.htm

This is the issue with the mobile NVidia GPUs. Only a few Apple products were repaired for free, the rest are assumed to be working normally. NVidia even admitted to their mistake and then what happened? 2007 imacs and some MBPs. Meanwhile, the early 2008 imacs with the new 8800 can't possibly be made differntly since the issue hadn't been revealed yet.

I've used this technique on XBoxs to fix the RROD, and I might just try it on my imac It may be hardware now, but it was a software update that caused the hardware to run hotter.

I am proud to say that I successfully rebaked my 8800GS and repasted both the CPU and GPU to their heatsyncs and cranked them down in hopes to lessen heat warping which leads to the solder cracks.

My GPU and CPU run AT LEAST 20F cooler than before. I've had it on for almost an hour now. Compare to yours.

http://img192.imageshack.us/img192/53/screenshot20101212at908.png

It's a little bit of a pain to get to the underside of the logic board, but once you did it a time or two, it gets much easier. (I forgot something and had to go back.)

I baked the GPU at 400F got 12 minutes on foil balls with foil covering the little tiny capacitor that is normally covered with foam. I let if cool for 40 minutes or more before I started to reassemble.

I used Shin Etsu x23 Thermal Paste on the GPU and the surrounding chips (RAM?) and also cleaned and repasted the CPU as well to help keep ambient down a little.

For those out of options and don't find the 2 year old machines worth replacing yet, you might want to give it a shot.

I got a similar issue.

My machine would not boot pass apple logo.
Repair #1: replaced video card.

2 weeks later, same issue, I can boot into safe mode however but with garbled screen/barcode screen.
Repair #2: replaced video card + logic board.

2 weeks later again, same issue, I can boot into machine if disconnected from power source.
Repair #3: still in progress, technician called me and said that it's the LVDS cable (which kinda concerns me because the machine hangs and would shut itself down). I don't really think it's the LVDS cable but it's out of stock and still waiting for a repair.