I can't speak for the Peg, but I've had similar problems using TwinMos memsticks on several pc's. Some motherboards I've owned (MSI, Abit) won't even boot with TwinMos memory. (PC2100, CAS2.5 and CAS3)

Anyway, my point is: every brand of memory has faults, but in mine (and MorphDelf's) case, it seems as if TwinMos is "cheap" and "not so good"

I run PC2100 REG ECC ram in my peg, and never had any problems with it. (although it won't boot with more than 1gig :)