Help Needed: 2011 27" iMac with No Display - GPU Upgrade Dilemma

[marcoco]

Hello everyone,​

I recently inherited a 2011 27-inch iMac that’s giving me some trouble. The screen is completely blank, and I’m only seeing a white screen when I power it on. After doing some research, I found that the AMD Radeon HD 6970M (2GB) GPU is notorious for failing, which I suspect might be the cause of the issue.

To address this, I ordered an AMD M5100 GPU and installed it, thinking it would be a straightforward plug-and-play process like on Windows systems. However, I’ve come across information suggesting that I need to install OpenCore Legacy Patcher (OCLP) before the new GPU will work properly.

Since my display is completely non-functional due to the old GPU, I’m at a bit of a standstill.

My Questions:​

1. Is there any way to get a display output with the old GPU so I can install OCLP?
2. Are there any known workarounds to help get the new AMD M5100 GPU running on this iMac without having a working display?
3. Any tips or steps I might be missing to troubleshoot this issue?

I appreciate any advice or insights you might have. Thanks in advance for your help!

 

[Bigwaff]

Answers are within this thread or at least this thread best place to post questions -

2011 iMac Graphics Card Upgrade

iMac 2009 to 2011 MXM3 graphics card upgrade (Lastest update 10/13/2023 - this is the official documentation page - you found it finally!) This is the single and only documentation post. During the last years we constantly updated this post to reflect the lastet development of vBIOS and OCLP...

forums.macrumors.com

 

[Yebubbleman]

Hello everyone,​

I recently inherited a 2011 27-inch iMac that’s giving me some trouble. The screen is completely blank, and I’m only seeing a white screen when I power it on. After doing some research, I found that the AMD Radeon HD 6970M (2GB) GPU is notorious for failing, which I suspect might be the cause of the issue.

To address this, I ordered an AMD M5100 GPU and installed it, thinking it would be a straightforward plug-and-play process like on Windows systems. However, I’ve come across information suggesting that I need to install OpenCore Legacy Patcher (OCLP) before the new GPU will work properly.

Since my display is completely non-functional due to the old GPU, I’m at a bit of a standstill.

My Questions:​

1. Is there any way to get a display output with the old GPU so I can install OCLP?
2. Are there any known workarounds to help get the new AMD M5100 GPU running on this iMac without having a working display?
3. Any tips or steps I might be missing to troubleshoot this issue?

I appreciate any advice or insights you might have. Thanks in advance for your help!

Here's the problem (and why you're having to use OCLP at all), the AMD M5100, while slot-compatible with that iMac, isn't compatible with the OS insofar as there aren't official drivers for it.

What you MIGHT be able to do is install Windows 8.1 onto that machine and otherwise install Windows drivers for the AMD M5100 for it. I say Windows 8.1 because a 2011 iMac's components will definitely not have dedicated Windows 10 drivers (and Windows 11 drivers are so out of the question that it's not even funny). Plus, Windows 8.1 will have much newer security patches than macOS High Sierra (that Mac's final supported version of macOS) - albeit both are currently not getting any security updates whatever and are probably not the safest things to use on the Internet in 2024.

All in all, it's a cool project that you're trying to do, but the end result isn't really all that practical.