From what I can gather, it's software or driver issue that may or may not have been patched. Or at least the main streaking issue was but now there are other issues like graphical glitches during shutdown etc.I’ve read a bit of this……and am about to order a new iMac since I need both Mac OS and Windows…. Seems the 5700xt streaking issue was fixed? Heat? Gremlins? Only thing I really need a graphics card for is to potentially run Revit on the windows side…. Any of the cards should do the job but I like to future proof as much as possible, however I’m honestly not certain if the 5700 or 5700xt are safe bets.
I did a fair bit of digging around to work out the performance difference between iMacs with a 5700 vs the 5700XT and my best estimate is the 5700XT is somewhere between 8-15% faster for general 3D stuff (ie gaming) but seems to be a fair bit faster than that with anything that can properly take advantage of it's extra compute units. Not sure if Revit falls into that category or not but if it does then the XT might be a smart upgrade. Alternatively you could go a normal 5700 and use the cost difference to soup up something else like getting a bigger SSD.