nVidia GeForce 8800 GT Dying

[666sheep]

This is because with mini display port the maximum resolution you will get is only 1280 x 800 : http://support.apple.com/kb/HT3571
It's a hardware limitation with mini-display port on certain videocards.

This is in fact limitation of ACD 30, not the mDP

 

[pastrychef]

Another option would be an 8800GTS. I replaced my dead 8800GT with one of these and it ran much quieter and cooler due to the larger cooler.

 

[ChrisMc73]

If you prefer new one with warranty, get it form Apple store or any reseller (maybe you'll bet a better price, gotta check). If you'd want to lower the costs, you can grab used one from ebay: http://www.ebay.com/ctg/Apple-ATI-R...Graphics-adapter-/86102219#req_6_all_qqq_null for about $100 less than new one from Apple store.

I guess at this point I'd feel more comfortable buying it through a place that will give me the full warranty. So I guess Apple or a reseller, but I can only seem to find a brand new one on Apple and Amazon through a 3rd party seller, not sure their return/warranty on this card (ATI Radeon HD5770).

OWC has it for sale more than the Apple Store!