I have a new r5 1600af cpu I've been having issues with for a couple weeks now. I started with the stock cooler, which for a few days would max out at about 65-70c while gaming with stock settings + xmp. One morning it starting hitting 80c without any settings changed on my part, so I reinstalled the cooler with new paste several times but then it started reaching as high as 90-100c.
I picked up a decent new cooler, arctic freezer 33 esports one, and fresh tube of mx-4 recently but the temperature is still out of control. The only way I've been able to keep it in a semi-reasonable range is by turning off auto-OC, pbo, xmp, and offsetting voltage by -.100v (not sure the last one has actually had any effect) and even then it's totally inconsistent while ingame, ranging anywhere from as low as 40c, spiking and hovering at 75-80c, and even hitting low 90s on occasion. When totally idle, it remains at normal 30-40c but if I open up a youtube video it will fluctuate between 45c to mid 70s.
TLDR: cpu ranges between 40-80c while gaming with no OC or XMP and brand new cooler. It is possible that the cpu itself is defective? The temperature seems to be the only issue but I feel like I've tried everything in my capacity at this point.