I have been running unsupported Mojave on my late 09 27” iMac. It was working fine for a while, until it restarted, and I started getting this: Someone told me that it’s probably a bad graphics card. I removed the card, and this is what it looks like: There seems to be some discoloration in some areas, probably from high levels of heat. Would cleaning both the card and heat shield do anything? I thought maybe if I added new paste and thermal pads would do something. Or should I just look around for a replacement card?