iMac Mid 2011 GPU acceleration problem after installing Catalina dosdude1 Patcher 2020

[ranaharoon]

I installed successfully Catalina using dosdude1 patcher on my iMac (21.5-inch, Mid 2011). As it has "AMD Radeon HD 6750M 500MB" graphic card so GPU didn't work. i got no hardware acceleration which made my graphics performance laggy poor, sleep & brightness functions didn't work either. I tried kexts files solution using Kext Utility & hackingtool which places files in "/System/Library/Extensions" it didn't show any luck. Then I installed Catalina from same usb drive on another iMac (21.5-inch, Mid 2010) it has "ATI Radeon HD 4670 256 MB" graphic card. Here everything worked fine including brightness, sleep and GPU acceleration even used after effects and rendered some videos too. Then I copied it's AMD named Kexts files from 'Extensions' directory in flash drive and placed them in Mid 2011 machine where I had laggy display issue. My Brightness and Sleep issue got resolved but GPU acceleration problem stood still.

After researching few days i couldn't find any GPU acceleration solution for iMac Mid 2011 (as model identifier iMac12,1) after finding the possibility of adjusting/fixing of these both cards I found they are in same size, then i just took "ATI Radeon HD 4670 256MB" graphic card from Mid 2010 and put it in iMac Mid 2011 and exchanged it's with the iMac mid 2010. Because acceleration did work on Mid 2010 but unfortunately "ATI Radeon HD 4670 256MB" didn't work in iMac mid 2011. I tried reinstalling Catalina, reapplying Kexts files with all previous approaches including this one, as well as did fresh installation using same dosdude1 patcher, tried removing video legacy patcher but got no luck. instead exchanging the card showed more bad laggy performance than before on mid 2011. I'm attaching details if someone could help me out with this. All I need to use Xcode 12 that requires Catalina minimum. I would appreciate any advice you might have.

 

[r6mile]

This is a known issue - Dosdude specifically says:

• iMac11,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)
• iMac12,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)

If you want to use Catalina you should replace the GPU - check out the very comprehensive 2011 iMac Graphics Card Upgrade thread

 

[ranaharoon]

This is a known issue - Dosdude specifically says:

• iMac11,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)
• iMac12,x (systems with AMD Radeon HD 5xxx and 6xxx series GPUs will be almost unusable when running Catalina.)

If you want to use Catalina you should replace the GPU - check out the very comprehensive 2011 iMac Graphics Card Upgrade thread

I've read that. but as it worked perfectly on iMac mid 2010 with "ATI Radeon HD 4670 256 MB" I though it's more about card as dosdud1 mentioned that from "AMD Radeon HD 5xxx to 6xxx" could face issues. But this one is *ATI Radeon HD 4670* which is less than it. So I thought it should work in iMac mid 2011 too. but it didn't. Dosdude1 also mentioned it's GPU is changeable or upgradeable so my question is, what card can I use for iMac mid 2011?

Another question, can I exchange their processors & rams, ssds? This means I want to install Quad-Core 2.5 intel Core i5, 16GB 4rams, 1SSD in Mid 2010 from Mid 2011. and 3.0 Dual-Core intel Core i5 in Mid 2011 from mid 2010. I believe if it's possible then Catalina is working with Radeon hd 4670 card already and I best just transfer these parts. Is it worth doing that?

 

[Nguyen Duc Hieu]

Buy a K610m for a cheap solution.

 

[deenx]

I've read that. but as it worked perfectly on iMac mid 2010 with "ATI Radeon HD 4670 256 MB" I though it's more about card as dosdud1 mentioned that from "AMD Radeon HD 5xxx to 6xxx" could face issues. But this one is *ATI Radeon HD 4670* which is less than it. So I thought it should work in iMac mid 2011 too. but it didn't. Dosdude1 also mentioned it's GPU is changeable or upgradeable so my question is, what card can I use for iMac mid 2011?

Another question, can I exchange their processors & rams, ssds? This means I want to install Quad-Core 2.5 intel Core i5, 16GB 4rams, 1SSD in Mid 2010 from Mid 2011. and 3.0 Dual-Core intel Core i5 in Mid 2011 from mid 2010. I believe if it's possible then Catalina is working with Radeon hd 4670 card already and I best just transfer these parts. Is it worth doing that?

Maybe could be helpfull for someon. In order to user HD4670 in iMac mid-2011 A1312 - you should flash vbios to eDP.

 

[macguru9999]

If you are going to buy parts for a 13 year old mac have younsidered buying a 2012 or 2013 imac second hand instead ? that will run catalina and you might get one for a similar price... you can even upgrade to big sur with some patching