"Fast" "Slow" "Adequate" etc are all pretty subjective terms because they are relative to your personal need. As a hobbyist, I think my system is adequate (I’d like it to be faster) for my D800 photos and workflow. Professionals have business requirements for the leading edge because clients are waiting. I don’t, but like to imagine I do
Hopefully some of this helps you: Workflow: Aperture 3 for photo management and RAW editing, Adobe Photoshop CS4 for TIFF editing and plugins from Alien Skin, Imagenomic, etc Hardware: 2009 27” iMac 2.8GHz Quad Core i7 8GB RAM 1TB internal hard disk
-Downloading 100 RAW photos directly off the camera takes considerable time for transfer and initial processing. (I go do something else and come back) -Adjustments to RAW are nearly instantaneous. -Export RAW to a 50% JPEG takes ~5 seconds -Edit in External Editor takes ~12 seconds (includes Photoshop launch time)
The 1st three items assume that Aperture is the only program running. Use Aperture and Photoshop at the same time and it’s a slightly different ballgame.