blunt

yes your runs are better now, I remember yours were a bit slower too! Super pi is a single threaded bencmark, having more threads will only make it worse. disable two cores, it should get even faster. My Phenoms ran it the quickest on two cores.

Yes, 4.4 Ghz is extremely hard to get stable. You are stressing everything there, the CPU Itself, board everything. most people seem to run about 4.0-4.2GHz stable for everyday use.