Can Powercore Save My Imac? Options

[BigDawgES]

I've been dealing with the low power of my 400MHz iMac for some time now, saving money for a new machine. I desire to run CubaseSX on OS 10.2, using a variety of software synths as well as Reason 2.5 through ReWire.

However, I was contemplating the possibility of keeping my current machine and using TCWorks's PowerCore Firewire to handle all of my software synths. Is this a viable option, does that machine even work with sofware synthesizers, or does it merely provide effects?

Any input/other viable options would be greatly appreciated.