The effect of using the PAE switch on 32 OSs is NOT uniform based on how many cpu’s are in place. I’ve seen 1gb or less allocated to the OS and the remainder available for application use. When you expand beyound a single cpu, the partitioning of memory is not uniform either
the scheduler is very actively trying to spread out the load across multiple CPU’s. … Also PAE induces a translation table which degrades performance versus direct access. Memory above 4gb can only be used for db buffer space.