Thanks, IB. As usual, you have the best info.

I may play around with the /3GB switch to see how it affects the system. As I said, Photoshop is my big application. Memory demand has to do with slices, layers, filters, image stacks, history depth and working cache. I photograph with a Canon 1Ds Mark II, so I start out with big files: 16.7 megapixels. Processing with lots of layers, I have seen my usage go close to 1 GB, and I like lots of elbow room.

I don't think I would gain anything by going to XP-64. Do BOINC apps generally run faster?

PS. I'll do a short story on building this rig, with photos, and post it in Hardware.