Best way to test a L2 cache module?

[protocol7]

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.

[beachycove]

Sorry to hear this. They can be a little flaky for some reason.

Could it be a software glitch? Does anything else freeze up?

[protocol7]

I don't know if it was only affecting CD transfers, but in addition to causing DiskCopy checksums to fail, it also stopped Mac OS 8 from installing from CD (it failed part-way into the Mac OS install with an error). It took a while to narrow it down to the L2 cache as I was testing all the new stuff.

The thing is, I have a cache module for my 5400 which also misbehaves if it's installed. I could never figure out why. So I have cache modules for both of my OldWorld PowerMacs and neither are currently in use.

If the memory test passes the cache module then what else could be at play? Is there any voodoo involved in getting them to work OK?

[beachycove]

It is possible, I suppose, that the cache chip is not fast enough for the processor (150MHz 604?). If it was originally rated for a 120MHz processor, for example, it could be marginal.

There were certainly reports years ago of cache chips causing problems—in fact, problems galore with dual 604e cards.