The article mentions this, but this was before CPUs had lids. When delidding a CPU, you have to be very careful not to crack the silicon die that you are applying force directly to. In the case of this Athlon, even care wasn't enough.
First, the NexGen Nx686 prototype... that became the K6 after AMD bought NexGen.
https://web.archive.org/web/19990901212245/http://www.sandpi...
https://web.archive.org/web/20000831030211/http://www.sandpi...
https://web.archive.org/web/20000831030227/http://www.sandpi...
Second, the AMD K6 prototype... which came in a small footprint ceramic package.
https://www.cpushack.com/chippics/AMD/K6/AMDK6-Processor-CA-...
Third, the AMD K7... which also came in that small footprint ceramic package, on a Slot A PCB, with L2 cache chips.
http://www.cpu-galerie.de/html/amdk7athlonslot.html
Enjoy!
Thanks for the nostalgia trip.