There was a lively discussion at Nature Photographers Network-Digital Imaging Forum regarding very long 'save' times for Photoshop PSD files. One member there was frustrated that his save times for layered 500MB PSD files were taking up to 30s. These times were observed on a Puget Genisis with an i7-3.2 GHz, 16GB RAM, SSD main drive, and SSD PS scratch disk. I experienced similar times on my Puget Obsidian i5-3.3 Ghz, 16GB RAM, WD Blue HD's. Both machines running Win7-64 bit and Photoshop CS5.
We suggested system checks and tweaks to Photoshop--little or no change in the results. Both Puget machines are working perfectly, so what was going on, here?
One of the NPNers did some research and discovered that CS5 uses an algorithm that results in more accurate image files, but increases 'save' time. How about that!
If the save times for PSD files bother you, you can save them as uncompressed TIFF files. The file size will be larger, but save times are significantly reduced.
Hopefully, Adobe will tweak the algorithm in PSCS6 so that faster saves are possible.
PS: My Puget computer is 'da bomb'!