An article I found on Accelerate Your Mac recommended using DayStar's nPower Control for testing memory so I ran a 30 minute extended cycle with that. It passed without errors. But I'm having a weird corruption bug on my 7500 with a 256k L2 cache installed. If I try to mount a disk image in Disk Copy with verify checksum enabled, it will fail if the L2 cache is installed. With the cache removed it passes.