Could it be related to cache speed?

I do not think so, because other cpu (am5x86) run on 40x4 with out problems.

But... 5x86 cache speed is much slower than POD so It is possible that L2 can't handle. IT is very fast ISSI 15ns.

Anybody know where to find genuine 12 or 10ns? Chinese… 6$ for 5pcs sounds good but I am not gambler.

My observation:
When I set on jumpers WT L1 cache, The system is running much longer without bluescreen. On WB before desktop show-on it hangs and on WT it run few minutes more in Windows enviroment.