Did you validate the max MHz with CPuz of this chip?
Why using 4/4 and not 2/2 cores?
I also have 6800MHz Vali CPU, but 2D is not very good, so I'm interested in other spans between CPUz and 2D (1M/PiFast). It seems to be around 400MHz, but of course vali is very often with 1/1 and 2D with at least 2/2...
Good benching!