If you own an Intel motherboard with a Z170 or Z270 chipset, you might believe that it only supports CPUs up to Intel’s 7th generation, known as Kaby Lake. Even the CPU socket’s pinout …
They had integrated the L2 on-die before that already with the Pentium Pro on Socket 8. IIRC the problem was the yields were exceptionally low on those Pentium Pros and it was specifically the cache failing. So every chip that had bad cache they had to discard or bin it as a lower spec part. The slot and SECC form factor allowed them to use separate silicon on a larger node by having the cache still be on-package (the SECC board) instead of on-die.
They had integrated the L2 on-die before that already with the Pentium Pro on Socket 8. IIRC the problem was the yields were exceptionally low on those Pentium Pros and it was specifically the cache failing. So every chip that had bad cache they had to discard or bin it as a lower spec part. The slot and SECC form factor allowed them to use separate silicon on a larger node by having the cache still be on-package (the SECC board) instead of on-die.