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

[aa004737]

I am trying to upgrade my iMac 12,2 graphics card and I can’t figure out witch card is the best I have gone through all the documentation that it’s provided, my goal is to have a working iMac with Mac OS sequoia. I made everything work with the original hd6970 until it stopped working today. Does anyone have a working setup like the one I am trying to achieve so I can copy it.

4130. 4150

 

[dorninko]

I checked again to see what might be going on with the monitor and found another interesting quirk: if you set the brightness all the way to zero (everywhere — not just by writing it to NVRAM, but also by turning the slider to 0 in the system itself), then put it to sleep and wake it up, the screen magically comes to life and keeps working fine until the brightness is increased. What could this be?

Still sounds very random to me and I am pretty sure that the LED backlight is the problem. Easies way to find out would be to use another display. I had a very similar situation (sudden black screen at random situations, sometimes every few minutes sometimes after a few days. I was able to get the backlight back every time by applying sleep/wake) but was lucky because I had anothe iMac at home. I swapped the displays and the problem moved with the display.