I was a beta tester and can tell you the following things from my experiences:
1. Yes, she's CPU intensive. Even after a CPU upgrade.
2. However, I had the following observation. If you are working in 44.1 or 48k and have FAT enabled (for those of you who have not tried PSP's Master Comp or Master Q, FAT is a process that upsamples the audio within the plug-in, does the processing, then downsamples prior to output. It is defeatable, but is noticably more better sounding in terms of dimension and sonic clairity) then, it's a CPU hog.
HOWEVER, if you're processing 96k audio, you can bypass FAT (see the manual) as there is no need to upsample audio that is already at 96k. At that point, I've noticed that the CPU drain is a bit less, even though I'm running at a higher sample rate (we use SADiE, which offloads alot of processing to it's onboard processing card).
Hope this helps.
GH