Radeon HD video downgrade for patched-Mojave compatibility

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Level 1

8 points

Radeon HD video downgrade for patched-Mojave compatibility

Regarding the CTO 27" 2010 iMac with 2.93 GHz i7 processor, I attempted booting a machine of this model with a patched version of macOS 10.14 Mojave and succeeded, but true to warnings on the patch publisher's web page (dosdude1.com) video and other performance proved to be woefully inadequate. Apparently, neither that iMac's stock video card (ATI Radeon HD 5750) nor those of other 2010 iMacs (Radeon HD 5xxx series) can presently be made to work at all well with patched Mojave on unsupported Macs.

Reportedly, the 2011 iMacs with Radeon HD 6xxx series video cards also have this problem. However, the 2009s with Radeon HD 4xxx series video cards do not: They can run patched Mojave relatively problem-free.

Theoretically, a video card replacement might resolve this for me. The publisher says this himself in his instructional video for installing the patch (doing which to be clear he does not presently recommend for this model.)

In researching the practicalities of this, I have read that in general Nvidia MXM video cards can be considered for this upgrade. However, driver maintenance may be entailed, external power supply may be necessary (depending on card choice), and because these cards lack EFI a booting Mac's screen will remain dark until the login window presents.

Preferring friendlier options, I have researched further and learned that a 2009 or 2010 iMac's video card may be upgradable with a 2011's card. This makes me wonder: Can I do something like that but oppositely; that is, can I swap in the video card from a 2009 iMac for the card on my 2010 iMac?

Doing so would of course represent a downgrade in some degree. On the other hand, it could possibly have the special benefit of rendering my particular iMac patched-Mojave compatible.

Accordingly, I seek guidance. Has anyone thus downgraded their 2010 (or 2011) iMac’s video card or else confirmed the impossibility of so downgrading it?

Posted on Aug 7, 2019 9:06 AM

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Answer 1

ad_agency Author

Level 1

8 points

Aug 7, 2019 9:40 AM in response to rkaufmann87

The reminder about Apple-refurbished offerings is helpful. I had previously decided to consider purchasing a used 2012 iMac once received of any response to this posting.

I am also aware of the counter-culturality of my query. The question could have a factual answer about say whether any ATI Radeon HD 4xxx series video card pulled from a 2009 iMac will work in my machine.

Any such fact would in turn and of course would be subject to analysis. I welcome any and all.

Thanks for your analysis. I recognize its relevance and appreciate it.

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Answer 2

rkaufmann87

Level 10

141,078 points

Aug 7, 2019 9:11 AM in response to ad_agency

your machine simply is not designed to run anything beyond HS, you can hack it to make it work but your video is NOT upgradeable to Metal. In short, you are wasting your time (and ours I'm afraid to say) by pursuing this on these forums.

IMHO, if you want to run up-to-date versions of Mac OS, it's time to upgrade to a new Mac. If money is an issue and you are in the USA consider getting an Apple refurbished Mac. These have no down side, they are identical to a new Mac, have the same warranty as a new machine, are eligible for AppleCare and can save hundreds of dollars. If this is something you want to consider navigate to www.apple.com, go to the bottom of the page and click the Refurbished section. If you do not see what you want, check often as inventory changes VERY VERY fast.

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