Mid 2011 21.5" iMac GPU replacement

Oct 18, 2021
108
209
43
Ohio, USA
thehouseofmoth.com
As with most things, when too much information presents itself my mind locks up. Deciding which replacement GPU to put in a 2011 iMac is one of those cases.

I need GPU replacement that is not prone to failure like the stock 6000 series AMD card. 512MB or better, doesn't have to be the best, just functional. A metal card would be nice so this iMac can run Mojave or even Big Sur at some point perhaps. A drop in replacement would be best but if any flashing is required that's ok too (as long as it can be flashed from MacOS). If OpenCore is needed to make it work properly that's fine too.
All I have is the heatsink that's in this iMac, no other alternatives so can't do any hacking, modding or upgrading of that piece of hardware.

The iMac is not mine so:
- Must have boot screen
- Brightness control must work

There are hundreds of pages (https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/) with info. Again, when presented with that much info I just get github vibes and run.

Can anyone recommend the best, least hassle, GPU replacement for this Mid 2011 21.5" iMac? Any advice would be much appreciated!
 

davidg5678

Tinkerer
Oct 30, 2021
60
37
18
Hi! I upgraded my 2010 iMac's GPU about a year ago with an AMD WX4150. I have read all of the posts on that MacRumors thread for the last year as well. I am running macOS Monterey on my iMac right now, and it works very well.

With this project, there's really no perfect hassle-free GPU choice. It is a great hobbyist project but the upgrade requires considerable technical knowledge to perform and maintain. While there are lots of Nvidia cards available for purchase, they often have hardware faults that make the upgrade process more challenging than it ought to be. These days, Nvidia cards also receive worse hardware support. Unfortunately, there are not really any drop-in replacements available. This upgrade procedure is quite complex (and the documentation can be confusing), but it can make for a fun project. Some sellers on eBay claim to sell pre-flashed Nvidia GPUs, but often these don't even work, as is well documented on MacRumors.

Many of the pages on that thread are from people who bought defective used Nvidia GPUs and/or didn't read the documentation thoroughly enough before starting the project. I don't think reading hundreds of pages worth of threads is at all necessary to complete this project, but reading the first wiki post a few times in its entirety is an absolute must before starting the project. There are lots of small details there that end up being really important, so missing just one or two can leave one confused as to why their computer has a black screen, no longer chimes, or overheats after 5 minutes (all three of issues occurred for me before I did extensive troubleshooting).

I recommend that you select an AMD card for your iMac. As modern Intel Macs also use AMD GPUs, their software support is much better. A bonus is that they infrequently arrive dead-on-arrival the way Nvidia GPUs do.

I would advise you to not spend too much money on the GPU however, as it is important not to buy a GPU that is worth more than the iMac itself.

I think that the AMD WX4130 is a good choice at the moment (it is comparable to the WX4150 or RX460 in computing power). It has Metal support and will let you install modern macOS. In order for it to work in your 2011 iMac, you may need to first add a jumper resistor across two pads, as documented under "known AMD issues". It will not require any heatsink modifications to be compatible. This one looks like a pretty good price: https://www.ebay.com/itm/294496914579?epid=4032640048&hash=item4491624c93:g:5gsAAOSwqbBheESa

I would expect to pay around $75-$100.

You'll definitely need to install OpenCore and flash the GPU's vBios for the upgrade to work at all. Typically, people flash the vBios using a custom Linux live image running on a flash drive connected to the iMac (the upgraded iMac's screen will be black before the vBios is flashed, so another computer is used to SSH into the iMac blindly). This special Linux image is provided on the MacRumors thread. If you really want to do the flashing from macOS, there are clip-on USB ROM programmers available as also described on the MacRumors thread.

OpenCore will bring back a boot screen, as well as brightness control. It allows for upgrading the OS beyond macOS High Sierra too!

As you can see, this project isn't exactly hassle-free but provided you read through the first post's wiki instructions, you'll likely bring new life into an otherwise useless iMac. I can't emphasize enough how well my 2010 iMac runs macOS Monterey considering that it's 11 years old. I appreciate this upgrade, as it makes iMacs (which are otherwise e-waste), useful enough for modern work, despite their advanced age. I know you still can buy the same failure-prone ATI GPUs at a price premium, but I think that having the extra horsepower and ability to run macOS Monterey is where the GPU upgrade really shines.

Let me know if you have any questions. I'm happy to try answering them!
 

Garth Beagle

Tinkerer
Oct 28, 2021
25
25
13
I have a 2011 27" iMac with a failed GPU. I spent loads of time about a year ago looking into info on replacing it.

I ended up getting an NVIDIA K610M - IIRC, I'll need to at least flash it (blindly) and likely need to load OpenCore, so I can get backlight control (though, I'm not 100% sure, since I came across conflicting information).

But this is a project that hasn't landed yet, still up in the air..
 

grifty

New Tinkerer
Aug 7, 2022
6
1
3
Hi! I upgraded my 2010 iMac's GPU about a year ago with an AMD WX4150. I have read all of the posts on that MacRumors thread for the last year as well. I am running macOS Monterey on my iMac right now, and it works very well.

With this project, there's really no perfect hassle-free GPU choice. It is a great hobbyist project but the upgrade requires considerable technical knowledge to perform and maintain. While there are lots of Nvidia cards available for purchase, they often have hardware faults that make the upgrade process more challenging than it ought to be. These days, Nvidia cards also receive worse hardware support. Unfortunately, there are not really any drop-in replacements available. This upgrade procedure is quite complex (and the documentation can be confusing), but it can make for a fun project. Some sellers on eBay claim to sell pre-flashed Nvidia GPUs, but often these don't even work, as is well documented on MacRumors.

Many of the pages on that thread are from people who bought defective used Nvidia GPUs and/or didn't read the documentation thoroughly enough before starting the project. I don't think reading hundreds of pages worth of threads is at all necessary to complete this project, but reading the first wiki post a few times in its entirety is an absolute must before starting the project. There are lots of small details there that end up being really important, so missing just one or two can leave one confused as to why their computer has a black screen, no longer chimes, or overheats after 5 minutes (all three of issues occurred for me before I did extensive troubleshooting).

I recommend that you select an AMD card for your iMac. As modern Intel Macs also use AMD GPUs, their software support is much better. A bonus is that they infrequently arrive dead-on-arrival the way Nvidia GPUs do.

I would advise you to not spend too much money on the GPU however, as it is important not to buy a GPU that is worth more than the iMac itself.

I think that the AMD WX4130 is a good choice at the moment (it is comparable to the WX4150 or RX460 in computing power). It has Metal support and will let you install modern macOS. In order for it to work in your 2011 iMac, you may need to first add a jumper resistor across two pads, as documented under "known AMD issues". It will not require any heatsink modifications to be compatible. This one looks like a pretty good price: https://www.ebay.com/itm/294496914579?epid=4032640048&hash=item4491624c93:g:5gsAAOSwqbBheESa

I would expect to pay around $75-$100.

You'll definitely need to install OpenCore and flash the GPU's vBios for the upgrade to work at all. Typically, people flash the vBios using a custom Linux live image running on a flash drive connected to the iMac (the upgraded iMac's screen will be black before the vBios is flashed, so another computer is used to SSH into the iMac blindly). This special Linux image is provided on the MacRumors thread. If you really want to do the flashing from macOS, there are clip-on USB ROM programmers available as also described on the MacRumors thread.

OpenCore will bring back a boot screen, as well as brightness control. It allows for upgrading the OS beyond macOS High Sierra too!

As you can see, this project isn't exactly hassle-free but provided you read through the first post's wiki instructions, you'll likely bring new life into an otherwise useless iMac. I can't emphasize enough how well my 2010 iMac runs macOS Monterey considering that it's 11 years old. I appreciate this upgrade, as it makes iMacs (which are otherwise e-waste), useful enough for modern work, despite their advanced age. I know you still can buy the same failure-prone ATI GPUs at a price premium, but I think that having the extra horsepower and ability to run macOS Monterey is where the GPU upgrade really shines.

Let me know if you have any questions. I'm happy to try answering them!
Hello David i have a mid 2011 i mac and want to do what you did i changed the hard drive to a 1 tb ssd and put 20g of ram memory and now i want to install a new graphics card that you listed amd wx4150 my problem is i can't find it can you tell me where to purchase it and anything else you could tell me that would help Thank you in advance GRIFTY
 

davidg5678

Tinkerer
Oct 30, 2021
60
37
18
Hello David i have a mid 2011 i mac and want to do what you did i changed the hard drive to a 1 tb ssd and put 20g of ram memory and now i want to install a new graphics card that you listed amd wx4150 my problem is i can't find it can you tell me where to purchase it and anything else you could tell me that would help Thank you in advance GRIFTY
These WX4130/4150 AMD GPUs are still available for sale on eBay.com; however, unfortunately they cost 3x what I paid for them. My understanding is that many people on the MacRumors thread are now using cheaper comprable GPUs listed under the AMD GCN 1-3 section. I don't have any personal experience with these particular models though. I believe they have some quirks that make their setup procedure a bit complicated with 2011 iMacs (compared to 2010 iMacs, the 2011 models are more picky as a whole.)

My best advice is that you will definitely need to install Open Core Legacy Patcher and will definitely need to flash the GPU ROM on your iMac.

Do not hesitate to read the available documentation several times and take notes on the procedure. Also be aware that sometimes the information available is conflicting or outdated. Sometimes people get confused, ask questions, and recieve "read the docs" as their only reply. Don't get discouraged, and keep troubleshooting! If you have any questions, make sure to provide the experts on the MacRumors forum with as much detail as you can so they can help.

Good luck with your project! 👍

 
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grifty

New Tinkerer
Aug 7, 2022
6
1
3
Hello David
i don't mean to be a pain in the neck but i have been trying to order the wx4150 or equivalent video graphic card and searching at ebay numerous times without any luck. I am a retired guy who likes to tinker and likes a challenge and this is why i want to upgrade my 21.5 mid 2011 core i5 i mac like you did i'm not versed in computer lingo so if you wouldn't mind can you word it the way you would search ebay I appreciate anything you could do for me and my project
Thanks in advance again
grifty
 

davidg5678

Tinkerer
Oct 30, 2021
60
37
18
Hello David
i don't mean to be a pain in the neck but i have been trying to order the wx4150 or equivalent video graphic card and searching at ebay numerous times without any luck. I am a retired guy who likes to tinker and likes a challenge and this is why i want to upgrade my 21.5 mid 2011 core i5 i mac like you did i'm not versed in computer lingo so if you wouldn't mind can you word it the way you would search ebay I appreciate anything you could do for me and my project
Thanks in advance again
grifty
Here's what I searched for on eBay: https://www.ebay.com/sch/i.html?_nkw=amd+wx4150+mxm&_trksid=m5467.l1311&_odkw=and+wx4150+mxm

Keep in mind that you might need to solder a tiny SMD resistor to get the GPU to work --I only advise getting this GPU if you are comfortable with this procedure.
 

grifty

New Tinkerer
Aug 7, 2022
6
1
3
Hello David

For iMac 21.5" A1311 Mid/Late 2011 AMD upgrade Nvidia K2100m 2GB Video Card. Will this work to allow me to download the new OS Ventura?​
 

davidg5678

Tinkerer
Oct 30, 2021
60
37
18
Hello David

For iMac 21.5" A1311 Mid/Late 2011 AMD upgrade Nvidia K2100m 2GB Video Card. Will this work to allow me to download the new OS Ventura?​
The K2100M is an NVIDIA card, which means it will probably have worse support with macOS Ventura than AMD cards. Remember, that at this point in time, there is no support for macOS Ventura with any GPU model.

You may wish to consider the AMD M5100. I don't have any personal experience with it, but it is much cheaper and more widely available than other AMD GPU options. As I understand it, you'll have to disable the computer's sleep function, so that only the display goes to sleep but the rest of the computer always stays awake.

This M5100 model seems to be a popular GPU on the MacRumors thread as of late, but I'd advise you to ask for help regarding it there, as there are more experienced people who could help you with its specific issues.
 

grifty

New Tinkerer
Aug 7, 2022
6
1
3
The K2100M is an NVIDIA card, which means it will probably have worse support with macOS Ventura than AMD cards. Remember, that at this point in time, there is no support for macOS Ventura with any GPU model.

You may wish to consider the AMD M5100. I don't have any personal experience with it, but it is much cheaper and more widely available than other AMD GPU options. As I understand it, you'll have to disable the computer's sleep function, so that only the display goes to sleep but the rest of the computer always stays awake.

This M5100 model seems to be a popular GPU on the MacRumors thread as of late, but I'd advise you to ask for help regarding it there, as there are more experienced people who could help you with its specific issues.
Hello David
would this work? I'm sorry i'm so ignorant on this subject I really appreciate your time
 

davidg5678

Tinkerer
Oct 30, 2021
60
37
18
Hello David
would this work? I'm sorry i'm so ignorant on this subject I really appreciate your time
No, it is not an MXM GPU, so it won't fit. You would need to get an MXM type-A GPU.

You can find compatible parts if you search eBay for "wx4150 mxm". I see many suitable parts available for sale on eBay right now.

If you have other questions in the future, I think you will get better help on the MacRumors forum than I can offer here on TinkerDifferent, as there are hundreds of other people there with greater experience with this specific project.
 
Last edited:

grifty

New Tinkerer
Aug 7, 2022
6
1
3
Here's what I searched for on eBay: https://www.ebay.com/sch/i.html?_nkw=amd+wx4150+mxm&_trksid=m5467.l1311&_odkw=and+wx4150+mxm

Keep in mind that you might need to solder a tiny SMD resistor to get the GPU to work --I only advise getting this GPU if you are comfortable with this procedure.
Hello David
I just received my AMD GPU card it was flashed my question is you state that I may need to solder SMD resister. How would i know that? also paid 135.00 for the GPU not too bad
Thanks Again
Grifty
 

grifty

New Tinkerer
Aug 7, 2022
6
1
3
Hi! I upgraded my 2010 iMac's GPU about a year ago with an AMD WX4150. I have read all of the posts on that MacRumors thread for the last year as well. I am running macOS Monterey on my iMac right now, and it works very well.

With this project, there's really no perfect hassle-free GPU choice. It is a great hobbyist project but the upgrade requires considerable technical knowledge to perform and maintain. While there are lots of Nvidia cards available for purchase, they often have hardware faults that make the upgrade process more challenging than it ought to be. These days, Nvidia cards also receive worse hardware support. Unfortunately, there are not really any drop-in replacements available. This upgrade procedure is quite complex (and the documentation can be confusing), but it can make for a fun project. Some sellers on eBay claim to sell pre-flashed Nvidia GPUs, but often these don't even work, as is well documented on MacRumors.

Many of the pages on that thread are from people who bought defective used Nvidia GPUs and/or didn't read the documentation thoroughly enough before starting the project. I don't think reading hundreds of pages worth of threads is at all necessary to complete this project, but reading the first wiki post a few times in its entirety is an absolute must before starting the project. There are lots of small details there that end up being really important, so missing just one or two can leave one confused as to why their computer has a black screen, no longer chimes, or overheats after 5 minutes (all three of issues occurred for me before I did extensive troubleshooting).

I recommend that you select an AMD card for your iMac. As modern Intel Macs also use AMD GPUs, their software support is much better. A bonus is that they infrequently arrive dead-on-arrival the way Nvidia GPUs do.

I would advise you to not spend too much money on the GPU however, as it is important not to buy a GPU that is worth more than the iMac itself.

I think that the AMD WX4130 is a good choice at the moment (it is comparable to the WX4150 or RX460 in computing power). It has Metal support and will let you install modern macOS. In order for it to work in your 2011 iMac, you may need to first add a jumper resistor across two pads, as documented under "known AMD issues". It will not require any heatsink modifications to be compatible. This one looks like a pretty good price: https://www.ebay.com/itm/294496914579?epid=4032640048&hash=item4491624c93:g:5gsAAOSwqbBheESa

I would expect to pay around $75-$100.

You'll definitely need to install OpenCore and flash the GPU's vBios for the upgrade to work at all. Typically, people flash the vBios using a custom Linux live image running on a flash drive connected to the iMac (the upgraded iMac's screen will be black before the vBios is flashed, so another computer is used to SSH into the iMac blindly). This special Linux image is provided on the MacRumors thread. If you really want to do the flashing from macOS, there are clip-on USB ROM programmers available as also described on the MacRumors thread.

OpenCore will bring back a boot screen, as well as brightness control. It allows for upgrading the OS beyond macOS High Sierra too!

As you can see, this project isn't exactly hassle-free but provided you read through the first post's wiki instructions, you'll likely bring new life into an otherwise useless iMac. I can't emphasize enough how well my 2010 iMac runs macOS Monterey considering that it's 11 years old. I appreciate this upgrade, as it makes iMacs (which are otherwise e-waste), useful enough for modern work, despite their advanced age. I know you still can buy the same failure-prone ATI GPUs at a price premium, but I think that having the extra horsepower and ability to run macOS Monterey is where the GPU upgrade really shines.

Let me know if you have any questions. I'm happy to try answering them!
Hello David
I don't know if you remember me but you were helping me do this upgrade. I finally got it done and I just wanted to thank you for spending the time answering questions. I am running Monterey, I tried running Ventura but it was too choppy Thanks again David I could not have done this without you. YOU ARE THE MAN
Grifty
 
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