I found a pretty good Benchmark for Photoshop. Basically install this action, run it on the test image, and time how long it takes. Make sure you use these setting for consistency. and restart before you run it.
Post your time, Computer model, CPU, RAM, and scratch disk info. and photoshop version
1:54 Dell dimension 8400, 3.2ghz P4, 3GB of ram. 250mb external scratch disk, Photoshop CS2
(click Edit> preferences>general, then click next to go through the diff sections its self explanatory
1) History States = Set to 1
2) Cache Levels = Set to 4
3) Memory usage set to 100%
4) Set Any Processor usage to maximum (On laptops and iMacs, system preferences on a Mac)
Directions For Use.
1) Change settings to match above
2) Double click the action found in the action folder, this will install into the Photoshop Actions Palette. Or Copy the action and paste in the action folder in the photoshop folder Program files>Adobe>Photoshopcs2>Presets>Photoshop Actions. If its not in your actions palatte, click the little action menu on the top right of the palette and load acttion, browes to find it and load it.
3) Restart Your System (you might want to copy or print this page for reference)
4) Log back onto your computer and open Photoshop and only Photoshop. It is important that no other applications/programs are running.
6) In Photoshop Go to file>open> then navigate to the speed test folder and open the test image
7) Click Play on the Retouch Artists action In the Actions Palette and a dialog box will pop up (read it), get your stop watch or timing device ready and start at the same time as you click the continue button
8) Stop the clock when the test finishes, this is when the next dialog box pops up saying, “STOP”
heres a link of other results http://www.retouchartists.com/pages/results.html