Bad handling and bending the package, too much pressure on heatsink (pressing, rocking the heatsink too hard), causes this crack, Look at the edges are nicked badly. Lap your heatsink smooth with 600 to 1000 grit wet/dry sandpaper lightly, clean 3 times and very clean, and thermal paste replaced when reassembling.

I also have some nicks at edges of the die but did not crack them since I had been careful with them.

Cheers,

pentiumspeed wrote on 2021-04-11, 17:48:

Bad handling and bending the package, too much pressure on heatsink
Cheers,

I didn't think of that, thanks. I never actually used any of these CPUs, I just collect them. The last time I've seen cracks like that were on heat-damaged socket 370 Celerons and 462 Athlons. But the heatsink idea is more logical.

Are you sure those are cracks and not just scratches from the heatsinks or improper handling?

I recently took the cooler off an MSA R9 280 video card that was given to me because it was having issues and the die was scratched from the rough surface of the cooler base.

Yeah, those look like scratches on the surface.

might be the cause of the thermal compound used? Did you use IC diamond? or something like that?

It's hard to take a good photo of these they are so small. When I run my nails across the surface it feels jagged like a cracked surface.
They are almost identical and run through the entire surface of the die. I got them in this condition many months ago but I don't have socket P or any other notebook mainboards to try them. They don't show any sign of burns or discolorations like burned desktop Athlons or Celerons.
Pentiumspeed is probably right, someone must have over-tightened the heatsink screws.