WWWW - Ausdauersportler/IMAC-EFI-BOOT-SCREEN GitHub Wiki
What works with what?
Goal of this page is to provide tools, information, and software to upgrade your iMac using a working metal MXM3 slot GPU opening the gates to most recent macOS versions including Mojave, Catalina, Big Sur, Monterey, Ventura, Sonoma, and Sequoia.
This is not really a plug and play solution! You need some macOS / Unix system administration knowledge, the ability to run programs from the terminal app and some manual skills to assemble your iMac again. If you have not done this before, get some local help in advance and make a complete plan, look up the great guides on iFixit, get the tools, make notes while reading guides! Get a card, wait for another rainy Sunday and start your project and have fun!
Most software related changes are included in OCLP. I tried to add every feature we need with MXM cards in iMacs into this great project.
Please read me first!
Q: Which graphics card will work at all?
Only cards fitting into the MXM3 slot can be installed in the iMacs models listed below. Older iMacs have an MXM2 type slot which is incompatible with newer MXMX3 cards.
Q: Which MXM3 card will physically fit into my iMac?
There are smaller MXM-A cards which can be physically installed in all systems listed below. No heat sink mod needed, sometimes you need to ass a copper shim (15mm x 15mm x 0.5-1.0mm thick) to avoid contact/shorts of card and heat sink.
There are bigger MXM-B cards running stablely only in the 27" models. These cards can be installed into a 21.5" or 24" model MXM3 slot, but will be unstable due to their high power draw, will not fit onto the smaller heat sink, will over heat the iMac after a short while or simply not boot. Check the table below.
Nearly all MXM-B cards need the big three copper pipe MXM-B from the 27" mid 2011 model with the 6970M card to get the generated heat out of the system under load - the W6170M and M6100 and M61000 needs a small 7mm x7mm heat sink mod with a Dremel. The RX 5500 XT needs a heavy modification, the RX480 and WX7100 do not need any modification when installed on the 2011 big heat sink. All other AMD do not need modifications of the sink.
Q: Which card can be installed in my iMac model and will work properly?
You will find for every graphics card family a more detailed support table below.
| graphics card/iMac model | iMac9,1 24 | iMac10,1 21.5 | iMac10,1 27 | iMac11,1 | iMac11,2 | iMac11,3 | iMac12,1 | iMac12,2 |
|---|---|---|---|---|---|---|---|---|
| connector type | LVDS | LVDS | eDP | eDP | eDP | eDP | eDP | eDP |
| NVIDIA (EFI) | no | no | no | yes | yes | yes | yes | yes |
| AMD GCN 1-3 | yes | yes | yes | yes | yes | yes | no | no |
| AMD GCN4 | no | no | yes | yes | yes | yes | yes | yes |
| AMD RDNA | no | no | yes | yes | no | yes | no | yes |
- NVIDIA (EFI): EFI boot screen support, press alt/option on boot, Windows EFI/UEFI support, only eDP
- GOP: OpenCore for emulated boot picker (press ESC on boot, not alt/option), Windows UEFI support
- AMD EG2: EFI Boot screen support with iMac EG2 firmware modification, limited Windows UEFI support
- AMD EG: EFI Boot screen using the EnableGop driver enhancing GOP, Windows EFI/UEFI supporNVIDIA (EFI): EFI boot screen support, press alt/option on boot, Windows EFI/UEFI support, only eDP
- GOP: OpenCore for emulated boot picker (press ESC on bootQ: Which iMac models can be upgraded?
Q: Is there is a single optimal card?
No! Your iMac model, your budget, your comfort level with doing modifications, your ability to live with unresolved issues, your computing needs, the local market, etc. will determine the card to be used.
Q: Is there a most feature rich card?
There is a feature rich card - the AMD WX4130. But it will work only in eDP (see table below) iMacs without any physical modification using the EFI or GOP vBIOS. Like other GCN4 cards this model offers DRM, 4K HEVC, 4K H.265, VideoToolbox, and native macOS Monterey support. Still usable with patches on Ventura and Sonoma and Sequoia, but YMMV. Cannot be used in LVDS iMacs, unless you drive the internal display with a controller board and connect if to the external miniDP connector. Basically you converted the internal screen into an external screen.
Q: What are the most future proof cards?
AMD GCN4 and AMD RX 5500 XT cards - the latter still lacks Ventura, Sonoma, and Sequoia support with OCLP.
Q: Is there a card which will fit in all iMac models?
No, unfortunately not. Check the table above. No card will run in all iMacs properly regardless which BIOS you have flashed.
Q: Are there incompatible combinations of cards an iMacs?
Yes, there are! But there is a most compatible receiver, the iMac11,3 27, which can run literally every card tested, listed, or mentioned on the thread (iMac11,1 is compatibly in the same way). For all other iMacs you have to read and work through this entire page.
Read through this information carefully in order to choose the best card for your needs.
Q: Which graphics card will work at all?
Only cards fitting into the MXM3 slot can be installed in the iMacs models listed below. Older iMacs have an MXM2 type slot which is incompatible with newer MXMX3 cards.
Q: Are there incompatible combinations of cards an iMacs?
Yes, there are! But there is a most compatible receiver, the iMac11,3 27, which can run literally every card tested, listed, or mentioned on the thread (iMac11,1 is compatibly in the same way). For all other iMacs you have to read and work through this entire page.
Read through this information carefully in order to choose the best card for your needs.
Q: What does GOP and EFI mean at all?
GOP is an UEFI2.0 driver found in any properly flashed post 2012 graphics cards. Our iMacs uses EFI 1.1 drivers to provide the well known Apple EFI boot screen. The GOP driver - on the other hand - will provide an emulated boot picker (press ESC on boot, not alt/option) when using OpenCore boot loader and it provides Windows 10/11 UEFI driver support.
Since Apple owners are used to the EFI boot picker we developed drivers to support the EFI picker. All NVIDIA vBIOS have an EFI driver included, for AMD we have two different developments named EG2 and EG. We recommend using the EG version.
Q: What is the difference between AMD and NVIDIA cards?
AMD cards have better macOS support, in particular on Monterey and later and there is at least a single model for every MXM3 iMacs available. AMD GCN1-3 need 10.10, AMD GCN4 need 10.12 and Navi cards need 10.15 minimum to get macOS driver support.
NVIDIA cards lost support with Monterey. Patching started there an became with Ventura and Sonoma more and more difficult, expect to only limited support with Ventura and later macOS versions. Do not fall for old over priced 8GB cards just to run Big Sur. But you can run older macOS versions back to 10.8.3 using a NVIDIA card. You cannot use NVIDIA properly in LVDS iMacs (no EFI boot screen support).
Q: What is about other MXM3 cards?
Post High Sierra macOS support is limited to NVIDA Kepler GPU and AMD GPU from 2012+ (GCN1-4, RDNA), therefore we do not discuss the use of Maxwell or Pascal cards here, although these run perfectly with High Sierra, Windows, and Linux. Check this thread to get more information.
Q: What does patching with OCLP does to my macOS installation?
When Apple publishes a new macOS and drops support for older hardware usually drivers for older hardware will be removed from new macOS versions. To maintain support the OCLP team has to identify those drivers and re-insert them into the recent macOS. This sounds like playing with Lego (software) pieces, unfortunately it is much more complex. Starting with Monterey for Kepler and with Ventura for AMD this patching process could not completely recover full functionality. Patching is now altering the root volume installation provided by Apple. It needs lowering SIP (disable it partially, which cannot be enabled, again). One result is the loss of delta OTA updates. Whenever the update process starts Apple will notice the altered root volume and load a full installer to recover the complete installation. Finally Apple changed compiler flags for macOS and now it needs a CPU capable of running AVX2 instructions - another obstacle since no iMac CPU from the list above supports AVX2.
Working AMD graphics cards
AMD cards with LVDS support
Support for: iMac9,1 24" and iMac10,1 21,5
All details about LVDS support can be found in this post. Please also read this post to understand how to setup OpenCore through OLCP in advance to boot macOS properly.
There are different versions for iMac10,1 (EnableGop-LVDS) and iMac9,1 (EnableGop91-LVDS) - please check carefully which version you need. The bigger MXM-B cards will only fit into the 24" iMac9,1 with GT130 or ATI 4850 card. This GPU generation named GCN1-3 need macOS 10.10 minimum.
Modern graphics cards like GCN4 generation and later lack hardware support for LVDS signals. So we will not see any GCN4 cards with LVDS BIOS. But there is a hardware hack for the iMac9,1 and iMac10,1 to connect the internal LCD with a display driver board, rerouting the connector trough the memory door to the miniDP port. This makes the internal panel working as an external one and thus supports more recent GCN4 and NVIDIA cards - but without any brightness control. If you find a controller board with DCC tools like MonitorControl will work. Since the EFI picker will also show up on the externally connected internal display you could have everything what you want.
Cards can have different VRAM, please download the version matching your card.
LVDS GPU table
| Card | Boot Screen | Brightness Control | 21.5/24/MXM | Heat Sink Mod | OGL | MET |
|---|---|---|---|---|---|---|
| Venus family: | ||||||
| AMD M4000 | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 809 | 19 |
| AMD M6000 | yes (EFI) | yes (natively) | no/yes/B | 24 iMac9,1 only | 1010 | 30 |
| AMD M5100 | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 983 | 31 |
| AMD W5170M | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 932 | 30 |
| AMD M6100 | yes (EFI) | yes (natively) | no/yes/B | 24 iMac9,1 only | 1300 | 45 |
| AMD W6170M | yes (EFI) | yes (natively) | no/yes/B | 24 iMac9,1 only | 1500 | 45 |
The W6170M overheats the iMac9,1 on long Valley or gaming runs. So it is a working option unless you are abusing it. The older C2D CPU limits OpenGL test results while metal results remain the same. The W5170M needs this modification.
AMD GCN 1-3 cards
Support for: iMac10,1 27" - iMac11,1 - iMac11,2 - iMac11,3 only
This GPU generation is named GCN1-3 and needs macOS 10.8 minimum.
All EG and EG2 (both) EFI and GOP (no EFI, only OC picker) vBIOS version can be found on the external Github repository. Since there are similar cards with different VRAM, please download the version matching your card. The Info links below lead you to one or more posts where support has been announced for that particular card. Read the information published in those Info post.
known issues
- all cards listed below cause a crash on wake on iMac12,x systems (disable sleep) or severe NVRAM corruption on cold boot needing one or more PRAM reset to start properly. It is not a great idea to use such a card in the iMac12,x systems. A few cases were reported with working cards, in all cases the old 3.5 inch HDD was still in use. This device may cause some delays in the power on and wake process avoiding the GPU to fail (aka wake successfully).
- you need OpenCore (OCLP 0.4.0 and later) to setup and run those + cards, no EFI boot picker available
- check the vBIOS links for more details and compare OCLP generated config.plist with the settings there in case to trouble
- some cards cause additional SMBUS address problems (W6170M, W5170M), CPU thermal readings are partly broken (hardware issue, needs modding the card)
- W5170M does not run properly in the iMac11,2 (hardware issue, needs again this modification of the card), use Dell M5100 instead
- no card liste below will run properly in 2011 iMac12,x, please do not try unless you want to develop/explore a solution for the NVRAM corruption problems and failing start/reboot/boot problems happening on this machine, sleep and wake is broken using such a card
- VRAM support may not be complete, we have already created some special versions. So please visually check your own card and read the print on the VRAM chips to get the correct version to flash! Using the wrong vBIOS may brick your card and would need a clip to recover.
- GOP vBIOS version have problems to work/sync with external displays. sync needs display sleep, press SHIFT+CRTL+EJECT and wake the iMac up again.
- all MXM-B cards need a heat sink mod with a Dremel
GCN 1-3 GPU table
| Card | Boot Screen | Brightness Control | 21.5/27/MXM | Heat Sink Mod | OGL | MET |
|---|---|---|---|---|---|---|
| Venus family: | ||||||
| AMD M4000 | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 809 | 19 |
| AMD M6000 | yes (EFI) | yes (natively) | no/yes/B | yes, 2 pipe MXM-B | 1010 | 30 |
| AMD M5100 | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 983 | 31 |
| AMD W5170M | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 932 | 31 |
| Saturn family: | ||||||
| AMD M6100 | yes (EFI) | yes (natively) | no/yes/B | yes, 2 pipe MXM-B | 1024 | 30 |
| AMD W6170M | yes (EFI) | yes (natively) | no/yes/B | yes, 3 pipe special install | 1805 | 57 |
| AMD W6150M & E8870 | yes (EFI) | yes (natively) | no/yes/B | yes, 3 pipe special install | ||
| Tonga family: | ||||||
| AMD W7170M | yes (EFI) | yes (natively) | no/yes/B | yes, 3 pipe | ||
| AMD S7100X | yes (EFI) | no (hw mod needed) | no/yes/B | yes, 3 pipe | 1812 | 86 |
OGL column: OpenGL performance based on the Unigine Valley score from this table.
MET column: Metal performance based on MetalBench score from the table.
AMD GCN4 cards
Support for: iMac10,1 27" - iMac11,1 - iMac11,2 - iMac11,3 - iMac12,1 - iMac 12,2
known issues
-
some AMD cards will not POST (Power On Self Test) and will not run in the 27" Mid 2011. This happened with some WX7100 models, all RX480, some HP AMD cards. AMD WX7100 cards with a version number of 1.1 (search for a print on the front side of the card like V1.1 or VER 1.1) will work in all 27" iMac Late 2009- Mid 2011 while the version 1.0 will only run in Late 2009 and Mid 2010.
-
all RX470/RX480 cards are version 1.0 only - and do not work in Mid 2011 iMac systems!
-
some AMD WX4170 come with a blank EEPROM and are missing a resistor network. Working models with EEPROM are scarce. You can add a BIOS chip following this page. It requires soldering skills (ask cell phone repair shops)!
-
some AMD WX4130/WX4150/WX3200 need solder mods. There are multiple versions of this card - only the green "Dell" branded versions currently work in every supported iMac model except the iMac11.2. Other cards like the blue HP WX4150/WX3200 both need a mod to work in the 2011 iMac12,2 27 inch models, all Dell and HP cards need an additional to work in the iMac11,2 and iMac12,1 21.5 inch models. Check your card before applying any mod.
-
GCN4 cards cause a black screen on full boot running High Sierra. There are several work arounds.
-
WX3200 needs device-ID spoofing. OCLP will detect the GPU automatically on the first attempt and spoof the Polaris device-id correctly and automatically. Unfortunately on subsequent runs OCLP fails to distinguish a spoofed WX3200 from a real Polaris dGPU - therefore you need to set Settings->Advanced->Graphics Override to AMD Lexa manually to force the correct detection and build and install OpenCore, again.
-
all replacement cards support only one miniDP port in the iMac12,2 for external displays (the one close ot USB ports) while you can use the other one for ThunderBolt dongles and docks (and a 2nd display).
| Card | Boot Screen | Brightness Control | 21.5/27/MXM | Heat Sink Mod | OGL | MET |
|---|---|---|---|---|---|---|
| AMD WX3200* | yes (OC and EFI) | yes (natively) | yes/yes/A | no, special install | 1753 | 49 |
| AMD WX4130 ** | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 1805 | 53 |
| AMD WX4150 ** | yes (EFI) | yes (natively) | yes/yes/A | no, special install | 1805 | 62 |
| AMD WX4170 ** | yes (EFI) | yes (natively) | no/yes/B | no, special install | 2156 | 73 |
| AMD RX470 ** | yes (EFI) | yes (natively) | no/yes/B | no, 3 pipe 2011 | 2700 | 145 |
| AMD RX480 ** | yes (EFI) | yes (natively) | no/yes/B | no, 3 pipe 2011 | 2800 | 150 |
| AMD WX7100 ** | yes (EFI) | yes (natively) | no/yes/B | no, 3 pipe 2011 | 2949 | 170 |
OpenGL performance based on the Unigine Valley score from this table. T MET column: Metal performance based on MetalBench score from the table.
** These AMD cards are much more modern, but more difficult to source. Check the online offers carefully (the differences are explained above). The cards are be supported natively with Sierra and later. Latest known working macOS version is currently Monterey. Partial support on Ventura.
- The AMD WX3200 uses a simple Lexa GPU core, supported by macOS using a spoofing trick. It does not offer VA (needed for FinalCut and DaVince and similar) but DRM support. At a similar price the WX4130 is possibly a better choice. The card is relatively new from 2019.
AMD RDNA GPU
Support for: iMac10,1 27" - iMac11,1 - iMac11,3 - iMac 12,2
Lately some used RX 5500 XT MXM dGPU models were available in China built for crypto mining back in 2019/2020. Additionally Sonnet used different models (MXM non standard size) in their eGPU offerings. You find preliminary results with such a Sonnet RX 5500 XT AMD Navi GPU in iMac11,3. There is also a RX5700XT version of the Sonnet Puck, possibly one can find such a card in a few months cheaply on eBay... A full report about the cards from China can be found on the post following the ROM link below in the table.
This GPU generation named NAVI need macOS 10.15.5 Catalina minimum.
| Card | Boot Screen | Brightness Control | 21.5/27/MXM | Heat Sink Mod | OGL | MET |
|---|---|---|---|---|---|---|
| RDNA 1: | ||||||
| RX5700XT | yes (OpenCore) | no/yes/A | 3 pipe | |||
| Navi 14: | ||||||
| RX5500XT | yes (OpenCore / EFI) | yes (OpenCore / HW) | no/yes/B | absolutely! 3 pipe | 2729 | 233 |
| Navi 23: | ||||||
| RX6600M | yes (OpenCore / EFI) | yes (via HW PWM) | no/yes/B | absolutely! 3 pipe | 478 |
This RX5500XT is the ultimative GPU to be used in iMac12,2 systems. It offers support for at least two external displays and highest performance ever measured here.
The RX6600M behaves like a GCN4 VER 1.0 card and does not boot installed in iMac12,2. Successfully tested in iMac11,3. Although EFI picker technically works (to be used blindly) the screen remains black until macOS boots completely. Metal performance twice as good as RX5500XT.
Valley results were really similar regardless which resolution and quality I picked ( 2560x1440, normal 2455, ultra 2066 ) and (1920x1080 normal 2729, high 2371, ultra 2396). This is surely different from all other cards we ever had tested.
Which heat sinks can I use?
If you look closely into the GPU tables you will find a row named Heat Sink which indicates both the compatibility with your system (21,5 or 27) and if there is a physical modification using a Dremel needed. Since most people miss this crucial information I decided to collect it and put it here together again:
| Heat Sink Type | Thermal Design Power (TDP) | iMac Models (source) |
|---|---|---|
| MXM-A | 35W | used in all supported iMac models |
| MXM-B until mid 2010 | 50W | 27 iMac10,1+iMac11,1+iMac11,3 |
| MXM-B mid 2011 | 75W | only 27 iMac12,2 |
The MXM3 slot can handle enough current to provide 75W sustained in 27" models. So you can mix and match heat sink and cards between those bigger iMacs.
Solving this riddle from the other side one can list cards in the same TDP range:
| Thermal Design Power (TDP) | Card Name |
|---|---|
| <= 35W | K1000M, K1100M, K2000M, AMD M4000, K2100M, AMD M5100, AMD W5170M |
| 35W < TPD < 50W | AMD WX4130, AMD WX4150, AMD WX4170, AMD WX3200, AMD M6000 |
| = 75W | all other MXM-B cards listed here in the GPU tables |
All MXM-A cards will run on MXM-A heat sinks but you will observe higher fan speed needed compared with using the very same card type on a bigger MXM-B heat sink. The bigger the sink the more effective it will dissipate the heat. If you have a bigger sink please use it!
Please note the AMD M6000 and AMD WX4170 are full sized MXM-B cards and will not fit properly into 21.5 iMac models although the power draw is lower than 75W. @internetzel reduced the TPD of the RX480 to 67W just because users experienced shut downs in long gaming sessions. The fans cannot remove the heat from the big 27" iMac through the small holes in the top and bottom.
One can - of course - drill bigger holes into the bottom (air input) and top (heat exhaust) to avoid this.