Memory tests and HEXUS Pifast
There's nothing much to separate the two AM2 boards in memory bandwidth and latency. That's why the Pifast performance - which is the calculation of the constant to 10M places - is pretty similar. The inability to manually define the CAS latency on the Foxconn nforce570 SLI board hurts performance just a touch.
As an aside, look at how the Intel Core 2 Extreme X6800 makes mincemeat of the Pifast test.