Imac Ati Radeon Hd 4850 Driver Update Average ratng: 9,9/10 5141 reviews
The GPU board in your system is a premium GPU at the time. Not many people bought the high end system with it, so getting a replacement will be costly!Most are used boards taken from dead or part systems. So you do need to be careful where you buy it as they may not offer a replacement or your money back!Here's one source I have faith in for the GPU card:You might want to think if putting additional money into this system is worth it.
While still a good system, depending on what you are doing you might find a newer system will offer more performance. Yes, the newer systems are more locked in and maybe you just want to hold off until Apple intro's the new Mac Pro as its claimed to be a modular system.
Radeon Pro 560 Bootcamp Drivers
The new iMac Pro is a mean beast which for many may offer the needed performance but it does come with a cost.