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Thread '2011 iMac Graphics Card Upgrade' - Content history
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Preamble (Last Updated 07/11/2020)
You have probably found this thread because your iMac 2009-2011 is having problems caused by the graphics card. It is well known that these graphic cards are problematic/defective. You will find websites that encourage "baking" the card. Without getting into the technicalities, it will work but this does not repair the graphics card. In fact, it only delays the problem. We have great news for you! You can install another graphics card that does not require much more effort. In addition, this will allow you to install more recent versions of MacOS. This thread has over 300 pages of useful information BUT the good news is all of that information has been summarized in this first post. It is HIGHLY recommended that you read through this post before asking questions. Then, reread the information. You will appreciate that the more experienced users cannot spoon-feed all new users. This distracts them from working on the files and tools that make all of this possible. Enjoy!
Choosing the Right Card
This is the most important part of this process. The following information will help guide you in choosing your card. We have included the issues (loss of brightness control, loss of boot screen, loss of target display mode, etc.) to overcome when installing a non-stock card into a 2009-2011 iMac. When choosing your replacement graphics card, you must take under consideration: your budget, your comfort level with doing modifications, your ability to live with unresolved issues, your computing needs, etc. Unfortunately, this thread cannot help you source cards as there are two many variables involved. Read through this information carefully in order to choose the best card for your needs.
Important Notes Before You Begin
- The modified (video) BIOS version made by @Nick [D]vB, @nikey22 and @internetzel require an Intel i3 CPU or better. There is currently no way to make the features of these VBIOS working on Core 2 Duo systems (late 2009).
- Do not ask for custom BIOS support of cards that are not on this list. It takes several months of reverse engineering and testing before getting a new BIOS working. It took only six years for the first card here on this thread! If you would like to use a different card, consider yourself in unknown territory. Of course, let us know if it works! Chances are that Kepler based cards will run using the right (most likely Dell) BIOS but will exhibit the seven problems listed below.
- There are two type and sizes of cards: Smaller MXM-A cards and bigger MXM-B cards running stable only in the 27" models. While all cards will function in a 21.5" model, they are unstable due to their high power draw. @highvoltage12v tested a 770M here and had frequent Kernel Panics in macOS and BSoD's in Windows. Do not try it!
Card BIOS link Boot Screen Brightness Control 21.5"/27" Heat Sink Mod MXM Quadro K1100M + ROM yes (natively) yes (OpenCore) yes/yes no A Quadro K2100M + ROM yes (natively) yes (OpenCore) yes/yes no A Quadro K1000M * ROM yes (natively) no yes/yes no A Quadro K2000M * ROM yes (natively) no yes/yes no A Quadro K610M + ROM yes (natively) yes (OpenCore) yes/yes no A Quadro K4100M + ROM yes (natively) yes (OpenCore) no/yes yes, 3 pipe B GTX 765M * ROM yes (natively) no no/yes yes, 3 pipe B GTX 770M * ROM yes (natively) no no/yes yes, 3 pipe B GTX 780M * ROM yes (natively) no no/yes yes, 3 pipe B Quadro K3000M ** ROM yes (OpenCore) no no/yes ? B GTX 860M ** ROM yes (OpenCore) no no/yes yes B Quadro K3100M ** ROM yes (OpenCore) no no/yes yes, 3 pipe B AMD WX4130 ++ ROM yes (OpenCore) yes (natively) yes/yes no A AMD WX4150 ++ ROM yes (OpenCore) yes (natively) yes/yes no A AMD WX4170 ++ ROM yes (OpenCore) yes (natively) no/yes yes, 2 pipe B AMD WX7100 ++ ROM yes (OpenCore) yes (natively) no/yes yes, 3 pipe B
* BIOS by @Nick [D]vB that currently enable boot screens on your iMac, better performance, and BootCamp support.
** The GTX 860M does work using the linked BIOS. Multiple GPU cores were used on the GTX 860M in manufacturing, but only Kepler based cards work in iMacs. The K3100M works at least in a limited way as described by @Ausdauersportler in this post. The K3000M has been used with High Sierra by @Roman78. Using OpenCore all these cards can have a limited boot screen functionality, now.
+ BIOS by @Nick [D]vB and @nikey22 that currently enable boot screens on your iMac. Using OpenCore with these cards offers right now native brightness control, target display mode, UEFI Windows 10, and more! To enable backlight in UEFI Windows 10, see this post by @internetzel.
++ These AMD cards are much more modern, but are difficult to source. Check the online offers carefully (the differences are explained below). With custom BIOS and OpenCore, these are very compatible and offer native brightness control, boot screens, UEFI Windows 10, and much more modern capabilities and future-proofing than the NVIDIA cards. They also allow for Sidecar, H.264, and huge HEVC decode/encode gains in production. There are still some problems to solve.
- AMD WX7100 (recognized as Radeon RX 580 in macOS)
It is important to identify the card. This card has been unpredictable. @Nick [D]vB has obviously a working card with number 109-C95847-00C_02. @Pascal Baillargeau has a card working with number 109-C95847-00D_02. However, other users have not been successful with the same exact models. For example, @Vego17 recently got the same card as @Nick [D]vB. But his card did not work in his iMac 2011 while it does run normally in a Dell Precision 7710 laptop. - AMD WX4170 (recognized as Radeon RX 560 in macOS)
Some come with a blank EEPROM and are missing a resistor. Working models with EEPROM are scarce. User @jborko did a write up HERE on his experience installing a WX4170. You can use the 4GB version of the latest WX4150 rom too (refer to the table at the beginning). - AMD WX4130/WX4150 (recognized as Radeon RX 460 in macOS) - currently 09/10 Only
This card needs to have an EEPROM chip on board too. There are multiple versions of this card - only the "Dell" branded versions currently work. These WX 4130/4150 are not detected by the 2011 iMacs for some reason, and therefore are currently incompatible. Even worse, some models are not detected in any iMac model from late 2009 to mid 2011.
- The loss of EFI boot screen;
- The loss of backlight control;
- You can only connect one external monitor to 27" iMacs;
- The loss of Target Disk Mode;
- The loss of Target Display Mode (TDM);
- The loss of running the built-in Apple Hardware Test (AHT);
- The loss of temperature sensors on the new GPU.
You may use the OpenCore booter to add a boot screen feature to every card - even the Nvidia and AMD cards not listed here or known to have no BIOS support to show the original apple boot picker. There is a small delay between the chime (POST) and the initialization of the actual boot screen on the current NVIDIA modded BIOS. Most of the time (such as a quick reboot in macOS) the system boots too quickly for the EFI portion of the BIOS to initialize, making it appear that you may not have a "boot screen." All is working as intended if you can hold the "Option" key at startup and get a boot picker.
2. Native Brightness control is available for cards marked with + or ++ using a combination of custom BIOS and OpenCore.
For other cards, brightness control may be added in the future. Be aware that without brightness control, the iMac display runs at full brightness by default. For higher powered cards and 27" models, this can generate a lot of heat.
If you would like to "dim" your display using color dimming, many have used the app Brightness Slider, which is available on the App Store for free.
You can also use this app, which works better than most apps in the App Store, because it will dim the colors on the whole screen and it will display the built-in OSD, just like native brightness control.
Additionally, hardware level modifications using a DyingLight module or a Raspberry Pi have been used for brightness control. This software written by @passatgt can be run on a Pi for backlight control.
Last, but not least: User @Lottosmp came up with a solution based on the former engineering.
3. Despite having 2 miniDisplayPort outputs, the 27" 2011 iMac will only output to one external display. There is currently no fix or workaround for this.
4. Target Disk Mode is available on all cards marked with a + or ++!
5. Target Display Mode (TDM) is available on for cards marked with + when using both custom BIOS and OpenCore. Target Display Mode is *only* stable under High Sierra and should not be used in later OS's.
6. Apple Hardware Test (AHT): There is currently no fix for running the internal service diagnostics. You may search the net for the ASD (Apple Service Diagnostic) package instead. For each system there is a different package. Download and install the package onto a SD card or a DVD, which will give you full functionality. A working download link may be hard to find. It is not open source.
7. GPU Temperature Monitoring is available on cards marked with a + or ++when using both custom VBIOS and OpenCore. A modified version of FakeSMC and GPUSensors is included with the OpenCore bundle to allow monitoring of GPU temps. But you still have to use some third party tool to control the fans. The GPU die temperature is not available and (probably for that reason) the Apple SMC still not running properly.
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Q: Is this easy? I need a quick fix for my iMac!
A: Not necessarily. This "fix" is more of a "mod" to revive our iMacs. Depending on your scenario, it will require a full iMac disassembly, knowledge of BIOS flashing, dremel tools, heatsink modification, careful handling of logic board components, etc. With the used/grey market for many of these cards, other issues may pop up as well. Please inform yourself before undertaking this process.
Q: My system boots up, but I don't have internal display, any display, or my GPU is not recognized correctly. What do I do?
A: Your MXM card is likely running an incompatible BIOS and will need to be flashed with the correct one. This can be done from within Windows or Linux using NVFlash, or with a CH341a programmer.
Q: Flash VBIOS? How do I do that?
A: BIOS can be flashed in one of two ways: Either directly with a CH341a clip programmer or with the "NVFLASH" software in Windows or Linux. THIS POST helps describe the flashing process. Others have found THIS POST useful. User @xanderon created a pre-made USB that can flash Nvidia cards in the iMac with Linux over SSH. Many have found this the easiest method. There is an add-on to flash AMD cards using this method, too. Additionally, user @jowaju created a simple Installer package that can be run on macOS Sierra (10.12) and higher that creates a 15GB Windows 7 Bootcamp partition with all the needed tools.
Q: OK, so I need to use the NVIDIA web drivers, right?
A: No - all cards outlined in this guide use the included NVIDIA drivers in macOS. No additional GPU drivers are needed.
Q: Why aren’t you using Maxwell or Pascal cards in the iMac?
A: A lot of people here have tested Maxwell cards with their 2011 iMacs, and have had various issues from no internal display, no backlight on internal display and the card not hitting boost. Additionally, macOS Mojave (10.14) deprecated support for the NVIDIA Web Drivers which allowed the use of Maxwell and Pascal cards. For now, Kepler GPUs and the experimental Radeon cards seem to be our path forward.
Q: Can I use a 4K display with these cards? The original card doesn't support 4K.
A: Yes! So far, the K1100M & GTX 770M have been tested firsthand and successfully provide 4K@60Hz output via mDP to DP adapter on a 4K display. Others should work just as well.
Q: What paste is recommended to cover the VRAM/Components on the MXM card like Apple’s design?
A: For the GPU Die any thermal Paste like Thermal Grizzly’s Kryonaut paste is good for the Die. For onboard components, many recommend using K5 Pro Viscous paste instead of thermal pads, due to the unevenness of the heatsink, it’s also similar to Apple’s original Design: https://www.amazon.com/gp/product/B00K04D3UK/
https://www.computer-systems.gr/en/product-category/consumables
Q: What kind of performance can I expect after installing one of these cards?
A: We are still aggregating GPU benchmarks. You can help by running UNIGINE VALLEY on your iMac at 1080P MEDIUM and submitting the results HERE! You can also VIEW the results in real time HERE!
Q: Are there any internal modifications needed for an MXM-A swap?
A: For an MXM-A swap (the shorter/less power draw cards) there are no modifications that are needed for the heatsink on both the 21.5" and 27" model iMacs. The X-clamp still needs be removed from the back of the card and have the screw posts drilled or tapped out (or screws swapped) in order to fit the heatsink's screws. Separate the X-Clamp using a hair dryer before drilling or tapping - it is just glued to the board. Skipping this step can fry or damage your card. If you've cleaned your heatsink, be sure to re-apply thermal pads around the GPU VRAM to prevent contact with the bare metal of the heatsink. Use electrical tape to isolate card components from the sink! Watch closely after installing the card. Take a look at the attached pictures of this post!
Q: Are there any additional internal modifications needed for an MXM-B swap?
A: The MXM-B cards only work on the 27" models due to power restrictions. There is one additional mod needed to make the MXM-B card fit. First you must grind down your heatsink in the area where one or two large coils sit, this way the card will sit flush with the heatsink. You must prepare the the X-clamp in the same way as described with MXM-A cards above. Take a look at the attached pictures of this post!
If you have a 2 pipe heatsink that came with the lower end GPUs on these iMacs and want to use an MXM-B Card, you'll have to buy a 3 pipe heatsink to cool cards properly. You can get these on eBay.
Q: After GPU change my system does not boot at all, what is wrong?
A: Most likely the installation of card on the heat sink caused a short, or the card is simply faulty, or the card has not been reseated in the slot properly, check all this out first. Any hardware issue has to be solved by yourself!
Q: I want to help and experiment, what can I do?
A: First, read the full thread. Staying on top of the progress here is key! Currently, backlight mods in BIOS are being researched as well as boot screens and alternate video card solutions.
Installing OpenCore and macOS on your upgraded iMac
With the addition of our newer GPU, Metal is natively supported allowing for installation of macOS Mojave and Catalina with full graphics acceleration.
OpenCore / Catalina Loader:
Some of the below fixes are included in the OpenCore bundle! Please read the OpenCore post for more info. If you have previously modified your system for the below fixes, they will need to be removed to avoid conflict with the OpenCore injection. @herrdude provided an additional guide, another longer one by @Ausdauersportler and others named "Using Catalina Loader on an iMac" focussing on the special needs of 2011 models and special settings for AMD cards All guides are worth reading before starting the installation.
Installing macOS Sierra
Some users might see a black screen on macOS 10.12 "Sierra" after swapping to an NVIDIA card.
Link to information on getting macOS Sierra running with non-apple Nvidia graphics cards:
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-25#post-24105622
Installing macOS High Sierra
Until May 2020 the installation of High Sierra did not need any changes, but the most recent patch set delivered by Apple makes it necessary to install a modified kernel extension to avoid a black internal screen after reboot. It is basically the same kind of patch, needed for Catalina 10.15.4+, 10.14.6 (2020-003) & 10.13.6 (2020-003) will need it, too.
Installing macOS Mojave
Since you will have a Mojave compatible GPU, you could run the newest macOS without any serious issues. The recommended method is to have High Sierra as your primary OS and install Mojave alongside on a separate partition. So if anything goes wrong, you can still boot back into High Sierra to fix issues. You could preinstall Mojave before changing your GPU. Use dosdude1's Mojave patcher to do the install: http://dosdude1.com/mojave/
Important: while running the Post Install tool, make sure you deselect the Legacy Video Card patch option (since you will using a new, compatible metal graphics card).
Mojave 10.14.6 (2020-003) shows the black screen issue solved by this patched extension.
Q: Sleep is broken in Mojave, how do I fix this?
A: This is caused by the removal of the SandyBridge kexts in Mojave. Although we aren't using the iGPU, these kexts are still needed for proper sleep functionality. A zip file is attached with the proper kexts to restore sleep in Mojave. Inside the unzipped folder contains the App Kext Utility and the necessary SandyBridge kexts that need to be installed. Right click to open Kext Utility, then immediately quit. Select all the files inside the folder and drag them on top of Kext Utility and allow them to install.
Installing macOS Catalina
The process for Catalina is similar to Mojave as mentioned above. Similarly to Mojave, you could preinstall Mojave before changing your GPU. Use dosdude1's Catalina patcher to do the install: http://dosdude1.com/catalina/
Important: Post-install patching has changed since Mojave. Patching is now automated if your SMBIOS is detected to be an unsupported machine. Currently, only the 2011 iMacs have the "Legacy Video Card Patch" disabled by default. You will want to avoid this patch (since you will using a new, compatible metal graphics card) and will need to modify a plist file if you are using a 2009/2010 iMac with a Metal compatible video card. While building the patcher, you can go to the "Options" menu and de-select "Auto-Apply Post-Install Patches" to avoid this. See next question to manually fix this issue.
10.15.4 and later has been causing "black screen" issues for many folks. This is caused by a lack of kext initialization due to a lacking board-id in the AppleGraphicsControl.kext. A patched kext and a further explaination can be found HERE, thanks to @highvoltage12v.
Q: Sleep is broken in Catalina, how do I fix this?
A: Similar to the above issue in Mojave, the SandyBridge kexts are missing in Catalina. Installing them like Mojave fixes sleep, but causes extended boot times. @highvoltage12v has provided a patched IOSurface.kext containing the SandyBridge kexts in THIS POST which can be installed using the same method as above to resolve both issues.
Q: After installing Catalina on my Late 2009/2010 iMac my animations are broken/choppy, the Dock is grey and the menu bar isn't translucent. How do I fix this?
A: The dosude1 installer unfortunately automatically executes the "Legacy Video Card Patch" leaving Late 09/2010 MXM swapped users with broken/choppy animations. If you did install Catalina and would like to manually reinstall the stock Kexts and Frameworks, a guide has been written by @highvoltage12v to manually overwrite the patched files with stock files.
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Original Post from @MichaelDT June 14th, 2013.
I will be attempting to upgrade the MXM card in my 2011 21.5 iMac from the factory 6770m 512mb to a NVidia 675m 2GB. I choose this card because the chipset already has support from 10.8.3 onwards and affordability for an experiment. I am hoping that it will work without flashing like many of the other non MXM modern graphics cards (UEFI support) do in 64bit EFI Mac Pros ( I may loose the initial boot screen). But if all else fails I will attempt a flash. I will report back my findings when the card arrives (from Hong Kong). Wish me luck hopefully this will give those of us with the last modular iMac a path forward.