i have this problem with the l2 cache on palomino cpus as well , but only if i apply high vcore (2.1V+). with stock vcore i have the full 256kb l2-cache.
i think the l2-cache "problem" isn't cpu-z related, but cpu?
you can tell by the performance of the benchmarks the used l2-cache is really only 64kb then. so i don't think it's a read error by cpu-z