MP 1,1-5,1 Mac pro with sapphire hd 7950 no boot ... in trouble need help...

[John Brine]

Okay, so i have a mac pro 5,1 ( mid 2010) with a sapphire HD 7950 in it. Got up to Mojave by the usual way. Got it up to catalina with the help of dosdude 1’s catalina patcher. Was working okay up till a few weeks ago... so.. try recovery petition.. checked dosdude1’s faq-my hd is formatted as APFS, so no recovery partition. So.. make a bootable usb installer and start up from that... oookay.. so, managed to get to the startup manager after many tries... and usb installer shows up( mac os base system i think), pick it, click on the arrow, continue, so it tries to do that..gets to the loading screen, starts doing that... see the grey apple+ progress bar... buuuut... there are these little colored lines at the top of the screen... progress bar goes... colored lines stay... and it stalls at the end.the screen goes to black and stays like that. The graphics card fan doesn’t seem to be running at all as it should be. I have checked to make sure the graphics card’s power cables are plugged in and that the card is seated correctly in the x16 pci-x slot, which it appears to be. The switch on the card is in position 2 which is correct, at least for High Sierra and up it is. I have tried doing the reset smc/pmu thing a number of times.. didnt do much. Keyboard doesnt really respond that well, but it works. Tried to do the zap pram a number of times.. doesnt work reliably..after initial boot chime, maybe i get a white progress screen once, otherwise i get a black screen and am stuck in bootup loop...lots of chimes, even when i take my hands off the keyboard. So yeah... this card owes me nothing having served me faithfully for at least 10 years, maybe more... so is it worth me trying to fix it, replacing the thermal paste, thermal pads, maybe baking it in the oven, in the forlorn hope that i can pull off a miracle And raise the seeming dead. Or should i start saving up and go looking for a replacement-ish or maybe a better card that doesnt require the Pixlas mod( well, there goes the radeon vii even if i could afford it, and i think the vega 64 needs it too).. thanks for any help..john b...