12,x
Main Info Source
All the info is gleamed from the big macrumor's thread post #1. Be sure to consult the following sections. No way to link to these sections so perhaps open 2 browser windows to read side by side this site and these sections
Spoiler: 2 Working AMD Graphics Cards
Spoiler: AMD GCN v4 GPU (2016-2017)
Spoiler: Known issues
Spoiler: Table of GCN v4 GPU and GOP vBIOS links
Spoiler: 3 Working NVIDIA Graphcis Cards
Spoiler: NVIDIA Kepler GPU (2013-2014)
Spoiler: Known issues or problems:
Spoiler: Table of NVIDIA Kepler GPU and vBIOS links
One Good Solution But Otherwise Difficult
iMac 12,x are the most challenging to upgrade to metal. The challenges are
Easy Low Cost Solution Does Exist
WX4130 Dell Green ver1.1 works well on latest macOS (Sonoma)
A few for $45 on ebay as of 1/2024
Stuck on Slightly Older macOS
All nVidia cards are only solid through Big Sur
Board Mods Complexity
Some AMD lower cost cards require soldering mods of various kind
Some AMD cards have different problems and mods for 12,1 (21") and 12,2 (27")
General Steps
Read Overview again :)
AMD WX4130 (only Dell Green Card ver 1.1)
This card works for all 2011 iMac 12,x Post #1 stated difficult to find (don't know when written) but few for ~$50 on ebay as of 1/24. Have confirmed card work solidly on Sonoma using OCLP!
All other working AMD cards seems to require soldering mods etc depending on Card model / version and iMac model. Avoidiing detailing these more difficult combinations for now.
vBIOS
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-30188251
ROM chip is low profile on this card so typical CH341A USB ROM chip flashing tool can't clip on to it properly. So the only vBIOS flashing solution is GMRL
Installation
12,2 require removing entire logic board to change GPU. More work than previous iMacs.
Guide / Summary
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-32918723
nVidia Kepler K610M K1100M K2100M
These are fairly low cost. K610M is < $20 on ebay @ 1/2024
Can't go past macOS Big Sur (using OCLP) without some problems.
Guides
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-32987261
27"