Certain older Macs are able to take advantage of adding an external graphics card through modification. This is article is broken up into 3 parts, as it contains a lot of information and pictures. Please refer to part 1 of the article for hardware/parts prerequisites. Sections 1 through 5 are contained in part 1, Sections 6 and 7 contained in part 2, Sections 8 through 10 are in part 3.
Jump to Section:
1: General Index
2: Hardware and required adapters
3: 1st Generation Apple TV
4: 2006 15″ and 17″ MacBook Pro
5: 2006 20″ iMac with ATI Radeon X1600
6: 2006 24″ iMac with GeForce 7300 GT
7: 2007 20″ iMac with Radeon HD 2600 Pro
|—7A: Here comes the fun part.. AMD Polaris + macOS Monterey!
|—7B: Switching to a Sapphire Pulse RX 580, Monterey 12.7.4, stable to this day.
8: 2006-07 Mac mini – (Last 3 sections pending Part 3)
9: 13″ MacBook with GMA X3100
10: Full GPU Compatibility List, all sections condensed
2006 24″ iMac with GeForce 7300/7600 GT
Of all the 2006 era non-pro Macs, the 24″ 2006 iMac is seemingly the most flexible/upgradeable when it comes to an eGPU. In my own testing, this iMac doesn’t have any of the RAM limitations the X1600 / GMA 950 chipset Macs do, being able to take 4 GB of RAM whilst simultaneously running a GPU.
- It’s been demonstrated the internal MXM GPU won’t stop a video signal going out the mini-PCIe slot – it will function akin to a dual GPU setup.
- Keep in mind, the further apart in age/OS the eGPU is from the original, the greater the issues will be in terms of functionality and compatibility. For example: A Radeon HD 2600 XT + the MXM 7600 GT can work together in Yosemite, but anytime anything renders on the older card, it slows down the eGPU since the 2600 has hardware acceleration, and the 7600 doesn’t in that OS.
- It is possible to run a low-power GPU entirely off of this iMac’s own internal PSU, but it’s not recommended due to risk of overloading the PSU. I’ve done this with the Radeon HD 2600 only XT (45W TDP), no issues in the 1.5+ years it’s been running like this! More information on how to perform this mod below.
On modifying this iMac to run eGPU off it’s own PSU
WARNING: Proceed with caution, and check thoroughly for power requirements of desired GPU. I am not responsible for any damages done to your iMac. Only tested up to a 45W card under this configuration.
- It is possible to supply: both the PCIe slot mini board and eGPU fully at the same time, if the chosen GPU has a low maximum Thermal Design Power.
- Since the Mac ATI Radeon HD 2600 doesn’t require additional power, only goes up to 45W under load, and provides a boot screen without any further modification, this card was a prime candidate. I actually push this card and do more than basic browsing, and nothing bad has ever happened!
- (Pictured, left): In order to connect the iMac’s internal display to this internalized GPU or to an eGPU, one must buy an LCD controller board for the LM240WU2(SL)(A
1) display. - I went a different route for the internal display: I found a 16:10 modern IPS LCD panel, fastened it to the iMac’s metal LCD brackets, used a separate power plug, and called it a day – rather than trying to figure out how to use the 06 iMac’s internal PSU to drive the display.
- I removed the HDD, replaced the HDD with an SSD. The original PSU is no longer driving the display anymore, it has its own separate power supply. The original MXM GPU is also removed – all this leaving more overhead for the iMac’s original PSU to power the HD 2600 XT all on it’s own, along with the rest of the computer.
- It’s possible to adapt a standard PSU to power both the logic board and GPU, especially if you just have a pile of 2006 iMac parts that you’d like to turn into a functioning computer.
(Above: Splicing the SATA Power out of the iMac for a 2nd plug, then adapting to 6-pin PCIe)
(Above: 7300GT working in tandem with the HD 2600. Click to enlarge)
(Above: I ripped out a 16:10 LCD from a monitor, and adapted it to this iMac)
(The setup finalized inside, before hooking up VGA to the new panel)
(Above: Unintended side-effects.. I had to remove the ODD..)
(Above: Project was a success! Click to enlarge)
(The same iMac, still running, as of 12/20/2024. Original LG panel died, was replaced by a Dell.)
2007 20″ iMac with ATI Radeon HD 2600 Pro
When fitting with an eGPU, this iMac is far more flexible than previous generations, and it seems to have less issues than previous Macs. Support seems to be more in line with the OS it can run, but there are hiccups here and there still. You’ll have better luck if you toss in a T9300/T9500 Core 2 Duo, as the Penryn architecture supports SSE 4.1. Later OS’s have better stability using Nvidia GPUs, and even PC AMD GPUs!
- Nvidia GPUs work with Nvidia Web drivers depending on the OS, but not always without them if you’re using an OS prior to Mojave. Even with the original MXM GPU removed, the Nvidia GPU may act unstable with “default OS X drivers”. Mojave through Big Sur is the sweet spot for “no Web drivers”, whereas Yosemite – High Sierra will be okay as long as web drivers are used, even in tandem with the Internal MXM GPU. It may be possible to have a Dual GPU setup on this iMac.
- On Mojave and later, the compatibility with AMD Polaris / Metal enabled GPUs seems to be 1:1 to the Mac Pro, with the exception of XFX-branded GPUs.
- A separate LCD driver board needs to be used for the iMac’s internal display. The one I purchased works off a 12V 3A Barrel-Jack style dell monitor PSU! No new display used, unlike the 24″ ’06 iMac project.
- OpenCore Legacy Patcher allows a boot screen to work, was tested successfully on a RX 570/580! When patching with OCLP, it’s best not to have the original MXM GPU installed. OCLP will patch for the old GPU, hampering any possible hardware acceleration out of the AMD Polaris GPU. As a result, it won’t show up properly in system profiler, but will still allow a video output in tandem with the original GPU.
- CAUTION: Better to buy an RX 580 versus a 570. I tested both an MSI / XFX RX 570, this iMac just doesn’t like the 570 after it’s installed for a while. Never a stability issue with the Sapphire Pulse AMD RX 580.
- Using an eGPU, you can drive both the internal iMac’s display and an entire 30″ Cinema Display.
- Unfortunately, this iMac doesn’t have AVX 2. Since Polaris drivers and much of the UI/system uses AVX 2 to in macOS Ventura and beyond, hardware acceleration is much slower/doesn’t function the same. The iMac will still work, of course, but Polaris GPUs are ruled out. Some more testing needs to be done with different GPUs, in the future.
- Display used in 2007 iMac: LM201WE3 (TL)(F6) – So you can find the right controller board.
(Above: Successfully testing a 2 GB EVGA GT 610 w/web drivers in 10.11.6, alongside MXM GPU)
Here comes the fun part.. AMD Polaris + macOS Monterey!
- CAUTION AGAIN: Better to buy an RX 580 versus a 570. I tested both an MSI / XFX RX 570, this iMac just doesn’t like the 570 after it’s installed for a while. Never a stability issue with the Sapphire Pulse AMD RX 580.
- Below: If you patch the HD 2600 Pro and THEN plug the RX 570/580 in, there will be display output, but it won’t show up properly. Original MXM GPU must be removed for macOS’s metal drivers to work. (click to enlarge)
- Monterey 12.7.1 21G920, Geekbench 6.2.2 tests: CPU / OpenCL RX 570 / Metal RX 570
- CPU: 598 (Multicore), 355 (Single Core) / OpenCL RX 570: 24469 / Metal RX 570: 26740
- After removing the HD 2600 Pro, an LCD controller board was installed, and plugged into the RX 570.
Switching to a Sapphire Pulse RX 580, Monterey 12.7.4, stable to this day.
- For some reason, the RX 570 kept overheating, even after applying a few different types of thermal paste, trying an extra 120mm blower style fan (before I ended up using it on the Power Mac G5), and multiple OCLP Monterey re-installs. It kept crashing and having “watchdog” kernel panics. I figured: Why not go with a supported, non-XFX GPU?
- Now, no matter the updates, the OS version, everything is stable! It can be pushed to run heavy games, Geekbench 6 no longer crashes when doing a Metal or OpenCL test, and thing can basically be used like a regular computer.
- Monterey 12.7.4 21H1123, Geekbench 6.3.0 tests: CPU / OpenCL RX 580 / Metal RX 580
- CPU: 541 (Multicore), 341 (Single Core) / OpenCL RX 580: 24232 / Metal RX 580: 26271
(Click to go back to top of article, or to Part 1)
