Get the most powerful modern machine you can afford (i7, Win 7, plenty RAM, 3 big drives) and use it as the “master”. Then press your XP machine into service IF you need to (as a slave running standalone VSTis via FXTeleport or similar … pipe its’ output into the master machine via the audio interface - as audio - and consolidate everything within a single Cubase project file in the master machine).
Don’t overwork this. My two years old computer works without a glitch and I probably do more busy stuff than you with more strange plugins. The meltdown of my old computer was a blessing in disguise, and it was a relief to not even have to think about if strapping yet another processor over an already processed track.
If you buy a capable computer with good hardware and avoid the latest and the fastest (new stuff is just expensive, but you know all about that) you won’t have to bother with more than one computer. It’s 2012! Don’t even think about it!
that’s my $2,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.23! 
wowzers
Hi Steve, first of all, please stop touching yourself! 
I am with Nick on this, you are better off just spending for some new muscle and using that as your master. You wouldn’t buy a Ferrari then tow it with a POS… I get where your coming from, but I think you’d ultimately limit yourself.
Well actually … if you buy a Ferrari, you will be towing it at-least-half-the-time with the POS. They’re not exactly known for reliability.
I think you’d find the difference between a system based on a Q9300 and say an i7 2600 more than “slightly lesser” if you look at it the other way round
http://www.adkproaudio.com/benchmarks.cfm
As can be see in the Dawbench DSP chart a Q9450 (slightly higher spec than the Q9300) managed 112 ReaFX ReaXComp ( Freeware ) @128
The i7 2600 can do 306 @128 sample buffer.
You can’t go wrong with ADK, Steve. The price you pay for a system that just works and a system that is tried and true. Their customer support is the best I have ever come across. If you figure the time it would take to build a system, configure it, iron out the bugs, optimize, test and set into service… your time is money, right? My next computer will be through them and it will be sooooo worth it.
I’m a big fan of ADK.
Yes I think so 
Of course the improvements are more than skin deep, faster ram, better motherboards, faster drives, etc…
Thing is, if you wait for the next improvement you’ll never jump as the next greatest thing is just around the corner.
5/6 years is about what one can expect from a system before it starts to get long in the tooth.
I totally agree with you, ones hard earned cash should be spent wisely. Just where do you jump in? 300% improvement 1000% or wait until quantum computing is common place
It is annoying, ending up with boxes of technology sitting about gathering dust because they don’t cut it any more. Trouble is the pace of change is accelerating, “the eons are closing” and someone out there wants your cash now.
Just as you invest in the great technology of today it becomes old overnight and tomorrow offers so much more. Headfirst into oblivion we go… hey ho
Steve, I’ve just finished a mix today for a client and even at 24/44.1 my machine was running at 80-90% on my i7 hex.
There were about 70 channels inc busses and FX channels,all audio no VI’s. Once you get into Slate consoles /Virtual tape, throw in some Nebula EQ’s you can see how even a powerful machine like mine starts to creak,even at 1024 buffer.
MC