Turning off dynamic accel helps about 5-10%.
Just finished installing 10.6.3 with minimum kexts (FakeSMC, NullCPUPowerManagement, TSCsync). Runs about 3x faster (i.e., normal). Removing NullCpuPower causes slow down on 10.6.3 again.
On 10.7.2 still can't get any improvement w same kexts (with or without NullCPUPowerManagement).
Trying to isolate the problem but it may be a kext in the system that requires removal (tried removing AppleGraphicsControl.kext with no improvement).
cheers