There is a thread about what computer to use, and here is a real life test you can all use to decide what you want to buy or build.
Using Photoshop CS or CS2 (or PS 7)
1.) Download Image from http://www.quicklance.com/test.jpg
2.) Save it to computer and then open it up in Photoshop
3.) From there please apply a 'radial blur' with the settings at:
Amount = 100
Blur Method = Spin
Quality = Best
Use the PS timer to see how long it takes to apply this filter. Run the test three times by closing the image each time and rerunning the radial blur test after opening the image fresh. Then average the three runs.
Now, here's the rub for those who wish to run another application while you work in Photoshop: Grab about 1GB of data and start the compression program Win RAR compressing the files (you can just select your entire image collection if you wish). I say use Win RAR because I know it pegs your CPU at 100% and must share the clock cycles with other apps running.
So start Win RAR compressing a bunch of files large enough to run the radial blur test three times, and then average it.
You can get a traial verison of Win RAR here: http://www.rarlab.com/
I don't think it ever expires, just nag screens you on start. I like it much better than Win Zip.
No applications running except Photoshop, firewall, virus protection, etc., and things like that.
AMD X2 64 4800 and an AMD FX 57 (I don't have the FX 57 any longer, but it ran with the same hardware below:
Mother Board: Asus A8N Premium SLI
RAM: 2 GB Corsair Extreme Pro (1 GB x2) Dual Channel mode.
Video Card: BFG Tech 7800 GTXOC
Only photoshop running:
X2 system: 35 seconds
FX 57 64 seconds
With Win RAR compressing files:
X2 system: 40 seconds
FX 57: 1:48
FX57 2.8 Ghz--the fastest single core desktop processor in the world at this writing: 64 seconds.
X2 4800 2.4Ghz Dual Core CPU: 36 seconds
All your regular programs running, virus scanners, firewalls, etc, plus Win RAR working on a 1GB file. Open Photoshop, and runt eh test:
FX57 1:49 secs
X2 4800 40 secs.
And there you have it. This also goes for other applications that you may want to run while you work in Photoshop, like Win Amp, Windows media payer, both to play music, a video conversion program, etc.
Speed comes at a rpice however, but do not be detered. Just buy one of the lower speed X2 Dual Cores and enjoy about the same speed for hundreds less.
AMD X2 4800 CPU: about 850.00