Scope uses DSP's
Kontackt and Gigastudio 4 hog the RAM and use light CPU cycles.
An excellent new BETA I just recieved has Physically Modeled instruments. These use RAM in smaller amounts, and a moderate use of the CPU. Since I just upgrade that CPU from the early E series to a new E8600 it nade that upgrade a worthy one.
These giant memory hogs from Kontackt 2 & 3 were pushing me towards the 64bit O.S. more and more, but the new BETA is a Grand Piano, w/ sostenuto pedals ( that actually work

Now for the first time I 'm actually using my available resources equally, and do not need to rush into a new O.S. or 64bit.
Scope can run my synths, hardware and software effects, mixers, B2003, Modular and Six-String.
GVI and K2 can run all of my libraries and Romplers, using mostly RAM.
The new BETA can do the Pianos and cash in those unused CPU IPS's, and 32bit will live on for another year or so.
This means a cheaper laptop if I chose to go that way.
Once someone gets rid of those cheezy IR's and FX that these sampler developers think sound good, the CPU usage is next to nothing.
A Big Sigh Of Relief.