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
iMac 12,x are the most challenging to upgrade to metal. The challenges are
GCN 1-3 GPUs don't work with sleep/wake so many lower cost choices are not viable.
WX4130 Dell Green ver1.1 (Sequia on 9/18/24)
nVidia Kepler GPUs generally have more problems > macOS Big Sur (Sequia test on 9/18/24 link )
cheaper WX3200 (as of 9/22/24) can be used if have reasonably good soldering tools and skills. See guide below
Read Overview again :)
This card works for all 2011 iMac 12,x (and all 10,x except LVDS and 11,x) Post #1 stated difficult to find. Generally pricier. Have confirmed card work solidly on Sequoia using OCLP!
All other working AMD cards seems to require soldering mods etc depending on Card model / version and iMac model. wx4130 bypasses these more difficult combinations for now.
EG1.2 ( link ) version ( link ) is better than one directed by post #1 Non EG1.2 vBIOS had random hangs on Sonoma (tested with 2 cards on 2 12,2) Avoid EG2 version unless you plan to flash the logic board ROM.
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
12,2 require removing entire logic board to change GPU. More work than previous iMacs.
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-32918723
This card works for all 2011 iMac 12,x (and all others except LVDS with the jumper removal mod) $30+ on ebay as of 10/24. Require simple soldering mod (but require good soldering tools and skill)
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-33432867
These are fairly low cost. K610M is < $20 on ebay @ 1/2024
Encounterd 1 card that wouldn't flash VBIOS (see details in macrumor's guide below)
macOS Big Sur runs best. After much work by the devs, macOS Sequoia runs quite well now ( post #22234 #22399 ) A member happy with Ventura link
https://forums.macrumors.com/threads/2011-imac-graphics-card-upgrade.1596614/post-32987261
27"
21"