Advice needed on graphics card replacement for Mac Pro 3,1 8 core

Hi All,
I'm not up on any of the hardware and thought I'd ask the group. I have a Mac Pro 8 core model 3.1 which I am running an older Cinema display (through the cable converter box) and a NEC 2690wuxi2. I'm experiencing some weird wonky screen scrambles from time to time - usually when I am doing longer photo edit sessions. Very often with Phocus, and Capture One but sometimes with other apps like lightroom. I am thinking my graphics card is getting hot and taking a break? Just thinking to replace my graphics card might take care of this and give a modest gain in performance too?

I see a Nvidia quadro 4000 and a radeon HD 5770 are compatible with my machine but suspect there are others too?

Anyone have any thoughts or recommendations?
Thanks,
Eric