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Hi, further to What GPU’s are compatible with iMac 27" 2011?, I am wondering what people’s experience has been with replacing the trouble-prone AMD Radeon 6970M with another Apple version versus a repurposed Dell/Alienware version? Does the Alienware version last any longer, or is the problem with the iMac’s thermal dynamics?
Lets first deal with the Dell/Alienware GPU board. The firmware on the board is not compatible with your iMac. You would need to burn a new chip with the Apple firmware or have a way to over-write the current firmware. As to why the GPU board fails: Not maintaining the system, cleaning the dust buildup and the thermal paste & pads on the CPU/GPU heatsinks.Running heavy graphics which the system was not designed to handle. The GPU in this series has its limits. Even the Dell and HP systems of the same age face the same failures! The solder joints tend to fail when the chip is thermally shocked This Is The Reason Why Graphics Cards Die - FlipChip Design - MicroBGA BGA. Newer GPU’s run cooler so this is less of an issue. While you can get a better GPU board (one with more VRAM) which will run better. You really need to keep the system clean and every three to four years replace the thermal paste & pads.
Hello, It is possible to replace the card with one of DELL MXM cards. For a 27”, the best choice is the Quadro K2100m as it runs cooler than the Radeon 6970m with a lower TDP and equal performance. Out of the box, you will get to macOS. But you will loose the bootscreen (can’t use the boot menu using the option key or access the recovery OS), no backlight controls and no target display mode. However, there is good progress made on this. This thread cover this well.https://forums.macrumors.com/threads/201… I upgraded my iMac and running Catalina as the Quadro supports Metal. Quite happy so far. As Dan mentioned, particularly in an iMac, dust and heat are the reason why the video cards are dying. I disagree that they are not designed to run intensive tasks. A GPU is design to run at 100% of its capacity when needed, especially without any overclocking, if it’s cooled properly. These machines were marketed by Apple for creative work not for word processing. The issue with iMac is the thermal solution is well under performing for this type of GPU and the thermal paste Apple uses is really bad. My current Radeon 6770m is still working. However, after my warranty expired, I took down the CPU and GPU, repaste with thermal grizzly paste, undust the fans and I have been doing that every 18 months for the past 8 years. The recent upgrade to the K2100m was more to get Metal support and upgrade to Catalina. Also, websites are getting heavy and just browsing apple.com on the AMD card was getting choppy. Cheers!
