iM 4,1-14,4 2011 iMac Graphics Card Upgrade

[NSteven]

Hi,

I'm running a WX4130 GPU in my iMac 27" 2011. Got macOS Sonoma via OCLP, dual-booting with Windows installed in UEFI mode.(Windows doesn't show in Startup Manager, so I use the OCLP picker to boot it.)

Issue: Using a Belkin Thunderbolt 2 Dock for USB 3.0. Works perfectly in macOS. But in Windows, with the dock connected and AMD GPU drivers loaded, I get a rainbow pattern on screen that fades to black. System is alive (keyboard/mouse make sounds), but no video output.

- Unplug dock -> Boots fine.
- Dock connected + default Microsoft Basic Display Adapter -> Boots fine.
- Only happens with dock + AMD driver.

Anyone seen this or know the cause?View attachment 2585786

Great news! On the iMac with the WX4130 graphics card installed, I fixed the screen corruption issue (like the photo I posted) when booting BootCamp Windows with the Thunderbolt dock plugged in.

The problem was caused by AMD XConnect Technology. XConnect is a feature for plugging in eGPUs, but it mistakenly detects the Thunderbolt dock as an eGPU connection(possibly due to EnableGop?) and disables the internal eDP output.

I confirmed this by connecting an external display via the Thunderbolt dock while the screen was corrupted, the external display worked fine, and the status bar showed XConnect running.

So, how did I solve it?
I completely removed the existing drivers and installed Radeon Pro Software 17.Q4 for DELL (probably from an era before XConnect), and it now works perfectly!!

 

[Pacific1972]

Okay so adding radpg=15 has allowed me to now use macOS, however the GPU comes up as a "AMD Radeon HD 7xxx" and also reads 890,000.000GB of VRAM? I think this has caused memory instability, I say this because every time something really Metal heavy or uses alot of VRAM that the card doesn't have (I think anyway) it beachballs and then takes me back to login or do anything at all. andNot only that OpenCore will not allow me to install the OpenCore EFI and comes up with an error which maybe because I do not have the ability to use the native mac boot picker. I need help please!

WWWW

How to create an EFI boot screen vBIOS for Apple Late 2009 to Mid 2011 iMac systems using AMD MXM graphics cards - Ausdauersportler/IMAC-EFI-BOOT-SCREEN

github.com

 

[Pacific1972]

Could anyone help with my iMac GPU upgrade? I have a flashed Dell FirePro M5100 Red PCB Hynix AFR EG2 VBIOS, so the VBIOS works. Ventura is installed, but booting shows a pure black screen (backlight off). Safe mode keeps backlight on and screen sharing works via MacBook, but no output on internal/external displays. Legacy GCN patches fail, and Monterey shows the same. I forgot exactly what but on my main Ventura install I changed something and got a cursor but yellow screen which seems to be more common? On OCLP 2.4.1 would disabling Library Validation and AMFI help at all too?

Do you have additional information (what iMac A1311 / A1312 - 2009, 2010 or 2011) ?

The EG2 BIOS is only for PCB-based / bridged Inverter-to-Power supply solutions (!), it can be
possible that this card have a same-adress thermal issue with CPU. This GPU is one of the cheapest
and worst solution for any iMac and manifests the differences between NVIDIA and AMD a few years
ago, unnecessary what other people say. You have the wrong BIOS (GOP or EG useable, not EG2) !

Other GPU should be better and if you buy this, don't use ALI or TEMU - the product quality
(DOA) of these sources are complete scam 😄 ...try US refurbishment centers instead !

 

[Aelean]

Hallo everyone, I didn't find any discussion of overheating in this thread, so I want to ask the following: I upgraded my imac 27 2011 to i7 2600 and gtx880m, everything works correctly, but in games the temperature reaches 90°C, which causes the card to reset frequencies from 930ghz to ~400, games start to freeze even at low settings. I adjust the fans, but it doesn't help, lowering the frequencies in afterburner is also useless. People with hot cards, what are your temperatures? Maybe I missing something?

 

[Pacific1972]

Hallo everyone, I didn't find any discussion of overheating in this thread, so I want to ask the following: I upgraded my imac 27 2011 to i7 2600 and gtx880m, everything works correctly, but in games the temperature reaches 90°C, which causes the card to reset frequencies from 930ghz to ~400, games start to freeze even at low settings. I adjust the fans, but it doesn't help, lowering the frequencies in afterburner is also useless. People with hot cards, what are your temperatures? Maybe I missing something?

Hmm, I hope that you have a VERY good thermal paste at the GTX880, the card uses sometimes 75W in idle
mode, but it can be that the GTX880 uses 100-125W under load !!! You should stay under 67° C with CPU and
GPU - that mean a thermal paste or a (Carbonaut) thermal pad with up to 62,5W / m*K.

But together with Core i7-2600 it can be limited by Apple power supply (310W), so the top level CPU + top level
GPUhave problems under massive load (almost in summer). I have tested a GTX880 with Core i5 based A1312
and the screen brightness goes down (!) 'cause of the max of 122W of the GTX880...

Hope this can help you... Good Luck !

 

[Aelean]

Thank you for the comprehensive answer. Well, can you tell me what thickness of thermal pads you use and how good an idea it would be to use liquid metal instead of thermal paste?

 

[Pacific1972]

Thank you for the comprehensive answer. Well, can you tell me what thickness of thermal pads you use and how good an idea it would be to use liquid metal instead of thermal paste?

I have no idea, what product you want to use, if you tell me something
about liquid metal 🤣 but if you mean that:

Thermal Grizzly - Conductonaut 73 W/mk​

I think that should be a good solution.

The thickness of thermal pads is not so important (if that fits between GPU and
heatpipe / heatsink), more important is the temperature-coefficient of the product.

 

[howardc64]

UPDATE 3 (1/16/26) : bootrom was not final High Sierra version. Corrected but the random crash persists. Post #22761

UPDATE 2 (1/15/26) : Despite working for a couple of hours post SMC+PRAM reset, a random crash occurred. Will monitor if gradually gets worse (higher frequency)

UPDATE 1 (1/15/26) : Issue below seems likely due to older/Samsung SSD corrupting NVRAM (Now running WD Blue SSD). A proper SMC reset seems to have resolved it for now. Will report back if anymore anomalies. Fairly easy to improperly do a SMC reset which is what I might have done before...

Proper SMC reset

• AC cord removed from iMac
• AC cord unplugged from outlet
• All accessory removed
• Wait 15s
• Plug everything back in
• Wait 5s, Boot, PRAM reset

I usually have a USB apple keyboard (Bt not working on wireless during boot) and USB dongle Logitech mouse. Easy to get sloppy and not unplug these

=====

2x iMac 12,2 + K2000M + SSD randomly crashes (screen goes blank and fan turns off, a few seconds later reboots : fan comes on and optical disc sound). First time I've tried a K2000M after 30+ Metal GPU installs including Kepler and AMD GCN3&4

iMac #1

• OCLP Sonoma
• Crashed yesterday during boot after not powered on for couple of weeks and previously used for few days without problem.

iMac #2

• OCLP Monterey
• Crashes soon after start. Sometimes before screen even becomes white during early stage of boot process. Sometimes can boot up to login and was able to collect the syslog

Both have the following

• K2000M flashed with nikey22 VBIOS from post #14582 per post #1 Kepler VBIOS table
• installed K2000M without shim (clearance looked okay, added Kapton tape where GPU faces logic board) on 2 pipe GPU heatsink.
• PRAM reset (frequently trying to resolve this problem)
• WD Blue 250 SSD with logic board fan spin solder bump mod to bridge TP[510]HDD_OOB_TEMP_FB to nearby ground plane ( link have done this mod on many 12,2 previously without this problem)

System.log isn't very revealing. Just shows random logging stopped just before BOOT_TIME (first syslog msg on boot)

I did replace one iMac with K610M and still had these crashes. But I might not have done PRAM reset or reinstalled OCLP macOS (I presume K2000M installation and K610M OCLP installations are identical since both are Kepler)

Have a couple of questions

• Anyone seen this kind of problem?
• Can logic board bootrom get corrupted? requiring flash?

I suppose there is a chance both K2000M could be bad. But it seems somehow the logic board got corrupted somehow.

 

[Pacific1972]

2x iMac 12,2 + K2000M + SSD randomly crashes (screen goes blank and fan turns off, a few seconds later reboots : fan comes on and optical disc sound). First time I've tried a K2000M after 30+ Metal GPU installs including Kepler and AMD GCN3&4

iMac #1

• OCLP Sonoma
• Crashed yesterday during boot after not powered on for couple of weeks and previously used for few days without problem.

iMac #2

• OCLP Monterey
• Crashes soon after start. Sometimes before screen even becomes white during early stage of boot process. Sometimes can boot up to login and was able to collect the syslog

Both have the following

• K2000M flashed with nikey22 VBIOS from post #14582 per post #1 Kepler VBIOS table
• installed K2000M without shim (clearance looked okay, added Kapton tape where GPU faces logic board) on 2 pipe GPU heatsink.
• PRAM reset (frequently trying to resolve this problem)
• WD Blue 250 SSD with logic board fan spin solder bump mod to bridge TP[510]HDD_OOB_TEMP_FB to nearby ground plane ( link have done this mod on many 12,2 previously without this problem)

System.log isn't very revealing. Just shows random logging stopped just before BOOT_TIME (first syslog msg on boot)

I did replace one iMac with K610M and still had these crashes. But I might not have done PRAM reset or reinstalled OCLP macOS (I presume K2000M installation and K610M OCLP installations are identical since both are Kepler)

Have a couple of questions

• Anyone seen this kind of problem?
• Can logic board bootrom get corrupted? requiring flash?

I suppose there is a chance both K2000M could be bad. But it seems somehow the logic board got corrupted somehow.

Hope (if you represents a bunch of experience) some thoughts can help.

I've burned down (a few years ago) 3x K2000 in 3 months with automatic fan control
in an A1311 and A1312 (only used 2011 models) - use manual rpm up from 2000rpm.

If using High Sierra without OCLP please use KEXTDrop and 2 modified KEXT files from
OC Loader based on a fresh install of macOS.

- I think you have made a ROM BIOS Update at the machines before installing flashed GPU.
- Some SSD won't boot with patched GPU models and modified macOS (KEXTs, OC Loader, OCLP).
- best choice for check GPU is High Sierra (native OS with driver support).
- I don't think that Monterey or Sonoma have native Kepler Support anymore
with a patched (GPU BIOS) + patched (OCLP "Kepler") core tweak.

But last but not least I think your K2000 GPU are both defected !

Sorry, but I never see such a HDD / SSD bypass mod at
HDD / SSD Bypass mod - do you have modify your Logic Board like this ?

 

[howardc64]

Hope (if you represents a bunch of experience) some thoughts can help.

I've burned down (a few years ago) 3x K2000 in 3 months with automatic fan control
in an A1311 and A1312 (only used 2011 models) - use manual rpm up from 2000rpm.

Interesting, were you doing graphics heavy stuff?

I use macsfancontrol and usually set ODD fan on GPU heatsink from 45C-65C for lower fan noise but ramps up quickly when running graphics heavy stuff. This is lower than your 2000 RPM lower bound of course.

If using High Sierra without OCLP please use KEXTDrop and 2 modified KEXT files from
OC Loader based on a fresh install of macOS.

- I think you have made a ROM BIOS Update at the machines before installing flashed GPU.
- Some SSD won't boot with patched GPU models and modified macOS (KEXTs, OC Loader, OCLP).
- best choice for check GPU is High Sierra (native OS with driver support).
- I don't think that Monterey or Sonoma have native Kepler Support anymore
with a patched (GPU BIOS) + patched (OCLP "Kepler") core tweak.

But last but not least I think your K2000 GPU are both defected !

Thanks for the numerous ideas. Despite SMC reset performing well for a couple of hours, iMac randomly crashed again Updated in the original post #22578. Will try High Sierra to check stability

As for other good practice suggestions

• I did get logic board ROM BIOS updated to High Sierra prior to GPU+SSD upgrade.
• OCLP Sonoma actually runs pretty well on Kepler. Posted a note in #22739. Do need to resolve the Software Update problem to Safari 26.2. But in general good to avoid Safari anyway on these patched macOSes due to deep macOS integration.
• I'll try native High Sierra and see if stable.

Sorry, but I never see such a HDD / SSD bypass mod at
HDD / SSD Bypass mod - do you have modify your Logic Board like this ?

Yes I've probably done like 15-20x 12,2s using this method. Works perfect every time. Have also done 10x+ 12,1 with the SATA connector pin 6+7 jumper in the same post. Also works every time. I do the changes on the logic board anticipating these iMacs will be on SSDs going forward.

For 10,x - 11,x (Apple changes HDD thermal solution so often between 09-11) On HDDs with thermal connector, I just do this 3904 transistor trick to silence the HDD fan.

iMac SSD Replacements

 

[howardc64]

A bit of an update on my iMac 12,2 random crash problems on post #22758

While testing in High Sierra (HS), saw 2020-005 update. To my surprise, this update flashed the logic board bootrom to version 87.0.0.0.0 Research shows this is the final version of the bootrom. So despite installing HS prior to the GPU upgrade, I didn't update logic board to the latest bootrom version.

These iMacs were running El Capitan (password locked and forgotten) and appears used as servers and never been upgraded to HS. My HS upgrade process is

• boot EL Cap from external USB drive
• run the HS installer to install to internal HDD (I've generally avoided network recovery of old macOS as more date related installation problems appear)
• The latest HS full installer is 10.13.6 (17G66) which flash bootrom version (IM121.004F.B00). Need to software update 2020-005 to get the latest 87.0.0.0.0

Didn't know how to do KEXTDrop and of OC Loader KEXTs with fresh HS install on VBIOS modded GPU so just use a USB drive with OC EFI as a boot selector to run stock HS.

2020-005 update flashing the bootrom was done with VBIOS flashed K2000M in the iMac instead of original GPU. Hope this doesn't cause any issues.

After HS 2020-005 (10.13.6 (17G14033)) AND 2020-006 (no bootrom flash) update, SMC + PRAM reset before installing OCLP Sequoia.

Result

iMac #1 is behaving pretty well. But this one has always run quite awhile before a random crash/reboot

iMac #2 12,2 Sonoma installation had random crashes but eventually got it installed (had to run post root patch which is not normal for OCLP 2.4.1, probably due to all the random crashes during OCLP macOS installation). Ran Unigine Valley for 3 hours with display set to turn off every 2min (to confirm this wasn't the crash problem) Then decided to reinstall OCLP Sonoma again (wipe drive, clean install) Unfortunately encountering random crashes even more frequently. Once crashes starts... seems to get worse.

Potential HW Issues

iMac #1 did have a dead PSU that was repaired ( LiteOn PSU repair link ) Maybe iMac #2 PSU could be suspect also as both iMacs was probably on most of the time used as servers.

Most random crash seems to occur during booting / installation. I think these are higher power draw phases so perhaps swap PSU with known good.

====

At this point with latest bootrom on the logic board + reliable WD Blue 250 SSD for older iMacs. Probably need to get a known good iMac 12,2 and start swapping parts to isolate failure.

 

[Pacific1972]

A bit of an update on my iMac 12,2 random crash problems on post #22758

While testing in High Sierra (HS), saw 2020-005 update. To my surprise, this update flashed the logic board bootrom to version 87.0.0.0.0 Research shows this is the final version of the bootrom. So despite installing HS prior to the GPU upgrade, I didn't update logic board to the latest bootrom version.

These iMacs were running El Capitan (password locked and forgotten) and appears used as servers and never been upgraded to HS. My HS upgrade process is

• boot EL Cap from external USB drive
• run the HS installer to install to internal HDD (I've generally avoided network recovery of old macOS as more date related installation problems appear)
• The latest HS full installer is 10.13.6 (17G66) which flash bootrom version (IM121.004F.B00). Need to software update 2020-005 to get the latest 87.0.0.0.0

Didn't know how to do KEXTDrop and of OC Loader KEXTs with fresh HS install on VBIOS modded GPU so just use a USB drive with OC EFI as a boot selector to run stock HS.

2020-005 update flashing the bootrom was done with VBIOS flashed K2000M in the iMac instead of original GPU. Hope this doesn't cause any issues.

After HS 2020-005 (10.13.6 (17G14033)) AND 2020-006 (no bootrom flash) update, SMC + PRAM reset before installing OCLP Sequoia.

Result

iMac #1 is behaving pretty well. But this one has always run quite awhile before a random crash/reboot

iMac #2 12,2 Sonoma installation had random crashes but eventually got it installed (had to run post root patch which is not normal for OCLP 2.4.1, probably due to all the random crashes during OCLP macOS installation). Ran Unigine Valley for 3 hours with display set to turn off every 2min (to confirm this wasn't the crash problem) Then decided to reinstall OCLP Sonoma again (wipe drive, clean install) Unfortunately encountering random crashes even more frequently. Once crashes starts... seems to get worse.

Potential HW Issues

iMac #1 did have a dead PSU that was repaired ( LiteOn PSU repair link ) Maybe iMac #2 PSU could be suspect also as both iMacs was probably on most of the time used as servers.

Most random crash seems to occur during booting / installation. I think these are higher power draw phases so perhaps swap PSU with known good.

====

At this point with latest bootrom on the logic board + reliable WD Blue 250 SSD for older iMacs. Probably need to get a known good iMac 12,2 and start swapping parts to isolate failure.

Dear howardc64,

I wrote something about KextDrop a few years ago (pre-OCLP-aera),
but you can find also the KEXTDrop App here somewhere + modified
AppleGraphicsControl.KEXT & AppleBacklightFixUp.KEXT extracted
from the OC Loader package - to copy that in S/L/E and isolate original
KEXT files to *.OLD !

Hope, this helps first with High Sierra (no OCLP needed until
upgrade to Big Sur and above) - have here Catalina Loader
and can extract some old files from the 16GB SD-Card.



This thread will soon be extinct, but:
Replacing the GPU only makes sense if the iMac A1311 or A1312 is assigned
for a task. Really good machines can sometimes currently be purchased for
€100 on eBay - (of course, only with a standard GPU & without SSD or 16GB) !