Thread '2011 iMac Graphics Card Upgrade' - Content history

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• General Questions (last update 04/04/2020)
  
  Q: What cards are working? Is there a list?
  A: Yes - specifics are below, but current working cards are:
  
  

  1. NVIDIA Quadro K2100M *
  2. NVIDIA Quadro K1100M *
  3. NVIDIA Quadro K2000M *
  4. NVIDIA Quadro K1000M *
  5. NVIDIA GTX 780M *
  6. NVIDIA GTX 770M *
  7. NVIDIA GTX 765M *
  8. AMD Radeon WX7100 **
  9. AMD Radeon WX4170 **
  10. NVIDIA GTX 860M ***

  While other cards may work, these are currently the recommended cards. If you would like to use a different card, consider yourself in unknown territory, and of course, let us know if it works!
  
  * These cards have modded VBIOS by @Nick [D]vB that currently enable boot screens on your iMac. In the near future, they might also allow for native brightness control, target display mode, and more.
  
  ** These cards are much more modern, but are difficult to source. With the latest VBIOS, these are very compatible and offer brightness control, boot screens, and much more modern capabilities and future-proofing than the NVIDIA cards, if you can find one. See "AMD" below for more info.
  
  *** The GTX 860M does work, but does not have a custom VBIOS like the others. Additionally, some cards will still need to be flashed with a new VBIOS for internal display functionality. Multiple GPU cores were used on the GTX 860M in manufacturing, but only Kepler based cards work in iMacs.
  
  Q: What new issues will I have after swapping my card with a PC MXM card?
  A: The biggest issues we have are:
  

  1. The loss of EFI boot screen*
  2. The loss of Backlight control**
  3. You can only connect one external monitor to 27" iMacs
  4. The loss of Target Disk Mode**
  5. The loss of Target Display Mode**
  6. The loss of running the built-in Apple hardware or ASD test
  7. The loss of temperature sensors on the new GPU

  * This means that when you start your iMac, you will have a blank screen until macOS boots up. Custom written VBIOS have been crafted for select video cards thanks to @Nick [D]vB but are still a work in progress. These VBIOS also enable Target Disk Mode. Currently, boot screens are only visible while holding the ALT or OPTION key at startup. This is a known bug, caused by the iMac booting faster than the EFI portion of the VBIOS initializes.
  
  11/24/19 - Kepler beta 3 VBIOS Released - the GTX 765M, 770M, and 780M GPUs can now display boot screens using @Nick [D]vB's VBIOS available here.
  
  12/7/10 - Boot screens are also available on Quadro cards using custom VBIOS available here.
  
  ** Native brightness control IS AVAILABLE for the Quadro K1100M and K2100M cards as well as the AMD cards! See latest post here using OpenCore. This also enables Target Display Mode on these cards!
  
  For other cards, brightness control may be added in the future!
  
  A guide to using the provided OpenCore disk image by @Nick [D]vB has been written by @herrdude on THIS POST.
  
  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.
  
  If you simply cannot wait for backlight control, hardware level modifications using a DyingLight module or a Raspberry Pi have been found to work great. This software written by @passatgt can be run on a Pi for backlight control.
  
  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 requires full iMac disassembly, knowledge of VBIOS flashing, dremel tools, heatsink modification, careful handling of logic board components, etc. With the used/greymarket for many of these cards, other issues may pop up as well. Please be cautioned before undertaking this process.
  
  Q: My system boots up, but I don't have a display or my GPU is not recognized correctly. What do I do?
  A: Your MXM card is likely running an incompatible VBIOS and will need to be flashed with the correct one. This can be done from within Windows using NVFlash. Common cards and their VBIOS are:
  

  • Quadro K1000M, K2000M, K1100M, & K2100M - Use Nick [D]vB's ROMs from THIS POST to enable boot screens.
  • GTX 860M - 80.04.E8.00.0D
  • GTX 765M/770M/780M - Use Nick [D]vB's ROMs from THIS POST to enable boot screens.

  Q: Flash VBIOS? How do I do that?
  A: VBIOS 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 the iMac with Linux over SSH. Many have found this the easiest method. 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 baked in 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.
  
  2009-2011 27” iMac MXM card upgrade Q/A
  Q: What MXM cards are known working?
  A: Unlike the 21.5" iMacs, the 27" models do not have any restrictions due to power draw. All GPUs listed at the top of this post should work in the 27" models. The MXM-B cards require heatsink modifications, but the MXM-A cards do not. See below for info.
  
  Q: Are there any internal modifications needed for an MXM-B swap?
  A: There are 2 mods needed to make the MXM B card fit. First you must grind down your heatsink in the area where two large coils sit, this way the card will sit flush with the heatsink. Second, you must drill out or tap out the rivets on Dell’s X-Clamp or grind away Apple’s X-Clamp so no capacitors or components touch the X-Clamp or sit under it. Skipping this step can fry or damage your card.
  
  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 out in order to fit the heatsink's screws. 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.
  
  2010-2011 iMac 21.5" iMac MXM card upgrade Q/A
  Q: What MXM card(s) are known working?
  A: Currently, the NVIDIA Quadro K1000M, K1100M, K2000M, and K2100M are the preferred MXM card's to swap due to space issues and low power draw of these cards. While the GTX series cards recommended above 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.
  
  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 out or tapped out in order to fit the heatsink's screws. 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.
  
  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
  
  Installing newer macOS on your iMac
  
  With the addition of our newer GPU, Metal is natively supported allowing for installation of macOS Mojave and Catalina with full graphics acceleration. See additional info below:
  
  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 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).
  
  Installing macOS Catalina
  The process for Catalina is similar to Mojave, 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.
  
  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 here to manually overwrite the patched files with stock files.
  
  "Unsupported" OS Fixes
  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.
  
  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: 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 VBIOS are being researched as well as boot screens and alternate video card solutions.
  
  AMD:
  
  See notes above. These cards are much more modern and offer a greater future-proofing than the NVIDIA cards but can be tough to source. Custom VBIOS and the newly released OpenCore boot disk allow these cards to have both native brightness control WIHTOUT a hardware level mod AND boot screens, and also allow for Sidecar, H.264, and huge HEVC decode/encode gains in production. See below for latest VBIOS and bootloader fixes.
  
  AMD WX7100
  Recognized by macOS as a Radeon RX 580, can be flashed for native brightness control, Target Display Mode, and more using custom VBIOS. Brightness control WITHOUT a hardware level mod AND bootscreens are possible on this card using OpenCore, see THIS POST for ROMs, Bootloader, and more info.
  
  AMD WX4170
  Recognized by macOS as a Radeon RX 560, but some come with a blank EEPROM and a missing resistor. Working models with EEPROM are scarce, but can be flashed for native brightness control, Target Display Mode, and more using custom VBIOS. Brightness control WITHOUT a hardware level mod AND bootscreens are possible on this card using OpenCore, see THIS POST for ROMs, Bootloader, and more info.
  
  ~~~~~~~~~~
  
  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.
• [B][SIZE=6]General Questions (last update 04/04/2020)[/SIZE] Q[/B]: What cards are working? Is there a list? [B]A[/B]: Yes - specifics are below, but current working cards are: [LIST=1] [*]NVIDIA Quadro K2100M * [*]NVIDIA Quadro K1100M * [*]NVIDIA Quadro K2000M * [*]NVIDIA Quadro K1000M * [*]NVIDIA GTX 780M * [*]NVIDIA GTX 770M * [*]NVIDIA GTX 765M * [*]AMD Radeon WX7100 ** [*]AMD Radeon WX4170 ** [*]NVIDIA GTX 860M *** [/LIST] While other cards may work, these are currently the recommended cards. If you would like to use a different card, consider yourself in unknown territory, and of course, let us know if it works! * These cards have modded VBIOS by [USER=1132239]@Nick [D]vB[/USER] that currently enable boot screens on your iMac. In the near future, they might also allow for native brightness control, target display mode, and more. ** These cards are much more modern, but are difficult to source. With the latest VBIOS, these are very compatible and offer brightness control, boot screens, and much more modern capabilities and future-proofing than the NVIDIA cards, if you can find one. See "AMD" below for more info. *** The GTX 860M does work, but does not have a custom VBIOS like the others. Additionally, some cards will still need to be flashed with a new VBIOS for internal display functionality. Multiple GPU cores were used on the GTX 860M in manufacturing, but only Kepler based cards work in iMacs. [B]Q[/B]: What new issues will I have after swapping my card with a PC MXM card? [B]A[/B]: The biggest issues we have are: [LIST=1] [*]The loss of EFI boot screen* [*]The loss of Backlight control** [*]You can only connect one external monitor to 27" iMacs [*][S]The loss of Target Disk Mode**[/S] [*]The loss of Target Display Mode** [*]The loss of running the built-in Apple hardware or ASD test [*]The loss of temperature sensors on the new GPU [/LIST] * This means that when you start your iMac, you will have a blank screen until macOS boots up. Custom written VBIOS have been crafted for select video cards thanks to [USER=1132239]@Nick [D]vB[/USER] but are still a work in progress. These VBIOS also enable Target Disk Mode. Currently, boot screens are only visible while holding the ALT or OPTION key at startup. This is a known bug, caused by the iMac booting faster than the EFI portion of the VBIOS initializes. 11/24/19 - Kepler beta 3 VBIOS Released - the GTX 765M, 770M, and 780M GPUs can now display boot screens using [USER=1132239]@Nick [D]vB[/USER]'s VBIOS available [URL='https://forums.macrumors.com/attachments/kepler-beta3-zip.878962/']here.[/URL] 12/7/10 - Boot screens are also available on Quadro cards using custom VBIOS available [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-28046843']here.[/URL] ** Native brightness control [B][U][I]IS AVAILABLE[/I][/U][/B] for the Quadro K1100M and K2100M cards as well as the AMD cards! See [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-197?post=28281414#post-28281414']latest post here[/URL] using OpenCore. This also enables Target Display Mode on these cards! For other cards, brightness control may be added in the future! A guide to using the provided OpenCore disk image by [USER=1132239]@Nick [D]vB[/USER] has been written by [USER=281385]@herrdude[/USER] on [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-28339811']THIS POST[/URL]. If you would like to "dim" your display using color dimming, many have used the app [URL='https://actproductions.net/free-apps/brightness-slider/']Brightness Slider[/URL], which is available on the App Store for free. You can also use [URL='https://github.com/passatgt/imac-pwm-control']this app[/URL], 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. If you simply cannot wait for backlight control, hardware level modifications using a DyingLight module or a Raspberry Pi have been found to work great. [URL='https://github.com/passatgt/imac-pwm-control']This software[/URL] written by [USER=585525]@passatgt[/USER] can be run on a Pi for backlight control. [B]Q[/B]: Is this easy? I need a quick fix for my iMac! [B]A[/B]: Not necessarily. This "fix" is more of a "mod" to revive our iMacs. Depending on your scenario, it requires full iMac disassembly, knowledge of VBIOS flashing, dremel tools, heatsink modification, careful handling of logic board components, etc. With the used/greymarket for many of these cards, other issues may pop up as well. Please be cautioned before undertaking this process. [B]Q[/B]: My system boots up, but I don't have a display or my GPU is not recognized correctly. What do I do? [B]A[/B]: Your MXM card is likely running an incompatible VBIOS and will need to be flashed with the correct one. This can be done from within Windows using NVFlash. Common cards and their VBIOS are: [LIST] [*]Quadro K1000M, K2000M, K1100M, & K2100M - Use [USER=1132239]Nick [D]vB[/USER]'s ROMs from [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-28046843']THIS POST[/URL] to enable boot screens. [*]GTX 860M - [URL='https://www.techpowerup.com/vgabios/205992/205992']80.04.E8.00.0D[/URL] [*]GTX 765M/770M/780M - Use [USER=1132239]Nick [D]vB[/USER]'s ROMs from [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-144?post=28011314#post-28011314']THIS POST[/URL] to enable boot screens. [/LIST] [B]Q[/B]: Flash VBIOS? How do I do that? [B]A[/B]: VBIOS can be flashed in one of two ways: Either directly with a CH341a clip programmer or with the "NVFLASH" software in Windows or Linux. [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-115?post=27787298#post-27787298']THIS POST[/URL] helps describe the flashing process. Others have found [URL='https://www.ifixit.com/Answers/View/296157/What+GPUs+are+compatible+with+iMac+27%22+2011#answer420333']THIS POST[/URL] useful. User [USER=1201679]@xanderon[/USER] [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-175?post=28184981#post-28184981']created a pre-made USB that can flash the iMac[/URL] with Linux over SSH. Many have found this the easiest method. Additionally, user [USER=1168330]@jowaju[/USER] created [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-191?post=28253271#post-28253271']a simple Installer package[/URL] that can be run on macOS Sierra (10.12) and higher that creates a 15GB Windows 7 Bootcamp partition with all the needed tools. [B]Q[/B]: OK, so I need to use the NVIDIA web drivers, right? [B]A[/B]: No - all cards outlined in this guide use the baked in NVIDIA drivers in macOS. No additional GPU drivers are needed. [B]Q[/B]: Why aren’t you using Maxwell or Pascal cards in the iMac? [B]A[/B]: 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. [B]Q[/B]: Can I use a 4K display with these cards? The original card doesn't support 4K. [B]A[/B]: 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. [B][SIZE=4]2009-2011 27” iMac MXM card upgrade Q/A[/SIZE] Q[/B]: What MXM cards are known working? [B]A[/B]: Unlike the 21.5" iMacs, the 27" models do not have any restrictions due to power draw. All GPUs listed at the top of this post should work in the 27" models. The MXM-B cards require heatsink modifications, but the MXM-A cards do not. See below for info. [B]Q[/B]: Are there any internal modifications needed for an MXM-B swap? [B]A[/B]: There are 2 mods needed to make the MXM B card fit. First you must grind down your heatsink in the area where two large coils sit, this way the card will sit flush with the heatsink. Second, you must drill out or tap out the rivets on Dell’s X-Clamp or grind away Apple’s X-Clamp so no capacitors or components touch the X-Clamp or sit under it. Skipping this step can fry or damage your card. [B]Q[/B]: Are there any internal modifications needed for an MXM-A swap? [B]A[/B]: 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 out in order to fit the heatsink's screws. 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. [B][SIZE=4]2010-2011 iMac 21.5" iMac MXM card upgrade Q/A[/SIZE] Q[/B]: What MXM card(s) are known working? [B]A[/B]: Currently, the NVIDIA Quadro K1000M, K1100M, K2000M, and K2100M are the preferred MXM card's to swap due to space issues and low power draw of these cards. While the GTX series cards recommended above will function in a 21.5" model, they are unstable due to their high power draw. [USER=883629]@highvoltage12v[/USER] tested a 770M [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-127?post=27861323#post-27861323']here[/URL] and had frequent Kernel Panics in macOS and BSoD's in Windows. [B]Q[/B]: Are there any internal modifications needed for an MXM-A swap? [B]A[/B]: 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 out or tapped out in order to fit the heatsink's screws. 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. [B]Q[/B]: What paste is recommended to cover the VRAM/Components on the MXM card like Apple’s design? [B]A[/B]: 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: [URL]https://www.amazon.com/gp/product/B00K04D3UK/[/URL] [URL]https://www.computer-systems.gr/en/product-category/consumables[/URL] [SIZE=6][B]Installing newer macOS on your iMac[/B][/SIZE] With the addition of our newer GPU, Metal is natively supported allowing for installation of macOS Mojave and Catalina with full graphics acceleration. See additional info below: [B][SIZE=4]Installing macOS Sierra[/SIZE][/B] 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: [URL]https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-25#post-24105622[/URL] [B][SIZE=4]Installing macOS Mojave[/SIZE][/B] 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:[URL='http:// http://dosdude1.com/mojave/'] http://dosdude1.com/mojave/[/URL] [B][COLOR=rgb(184, 49, 47)]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)[/COLOR][/B][COLOR=rgb(184, 49, 47)].[/COLOR] [B][SIZE=4]Installing macOS Catalina[/SIZE][/B] The process for Catalina is similar to Mojave, above. Similarly to Mojave, you could preinstall Mojave before changing your GPU. Use dosdude1's Catalina patcher to do the install:[URL='http:// http://dosdude1.com/catalina/'] http://dosdude1.com/catalina/[/URL] [B][COLOR=rgb(184, 49, 47)]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.[/COLOR] Q: [/B]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? [B]A: [/B]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 [USER=883629]@highvoltage12v[/USER] [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-28109056']here[/URL] to manually overwrite the patched files with stock files. [B][SIZE=4]"Unsupported" OS Fixes[/SIZE] Q[/B]: Sleep is broken in Mojave, how do I fix this? [B]A[/B]: 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. [B]Q[/B]: Sleep is broken in Catalina, how do I fix this? [B]A[/B]: 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. [USER=883629]@highvoltage12v[/USER] has provided a patched IOSurface.kext containing the SandyBridge kexts in [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-131?post=27899047#post-27899047']THIS POST[/URL] which can be installed using the same method as above to resolve both issues. [B]Q[/B]: I want to help and experiment, what can I do? [B]A[/B]: First, read the full thread. Staying on top of the progress here is key! Currently, backlight mods in VBIOS are being researched as well as boot screens and alternate video card solutions. [B][SIZE=6]AMD:[/SIZE][/B] See notes above. These cards are much more modern and offer a greater future-proofing than the NVIDIA cards but can be tough to source. Custom VBIOS and the newly released OpenCore boot disk allow these cards to have both native brightness control [B]WIHTOUT[/B] a hardware level mod [B]AND[/B] boot screens, and also allow for Sidecar, H.264, and huge HEVC decode/encode gains in production. See below for latest VBIOS and bootloader fixes. [B]AMD WX7100[/B] Recognized by macOS as a Radeon RX 580, can be flashed for native brightness control, Target Display Mode, and more using custom VBIOS. Brightness control WITHOUT a hardware level mod AND bootscreens are possible on this card using OpenCore, see [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-197?post=28281414#post-28281414']THIS POST[/URL] for ROMs, Bootloader, and more info. [B]AMD WX4170[/B] Recognized by macOS as a Radeon RX 560, but some come with a blank EEPROM and a missing resistor. [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-28299212']Working models with EEPROM[/URL] are scarce, but can be flashed for native brightness control, Target Display Mode, and more using custom VBIOS. Brightness control WITHOUT a hardware level mod AND bootscreens are possible on this card using OpenCore, see [URL='https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/page-197?post=28281414#post-28281414']THIS POST[/URL] for ROMs, Bootloader, and more info. ~~~~~~~~~~ [B][I]Original Post from [USER=728987]@MichaelDT[/USER] June 14th, 2013.[/I][/B] 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.