From Christian Holzapfel@21:1/5 to All on Thu Feb 23 07:19:10 2023
I have two working 730/750 systems, all with 256 KB of L2 cache onboard (8x cache SRAM + 1x TAG SRAM). None of them seems to see the cache in various test tools, and memory access doesn't slow down with the chips removed.
Jumpers are all set to 1-2 for "256 KB", and going for 512 or 1024 KB (in jumpers) doesn't change anything.
Tried with different RAM sticks (IBM FPM parity / non-IBM EDO non-parity), no change.
From Christian Holzapfel@21:1/5 to All on Thu Feb 23 07:41:11 2023
Other people on other boards seem to have similar issues with PC 340 or 350 models.
Strange there are sockets, IBM declaring cache as "optional", possibly billing customers for it but it's non-functional...
On one of the systems I had one dead out of the eight cache chips - the system wouldn't boot or even beep. Tried out by swapping them one after another until it worked again. So they're wired at least.