I didn't even know they did 6 gigs. Is that using the expansion slot? If not, I'd add in as much as you can.
I have a Vaio i5-2410 @ 2.3GHz with 8 gB ram (I got the 4 gB and then put in another 4 myself). It gets bogged down with intensive operations on large files, and I only do 16 bit, I'm sure 32 is going to give it trouble. But I've done plenty of work compositing multiple RAW images from a 20 mP camera with dozens of adjustment layers. But I'm also usually just about maxed out of Ram, with Photoshop, Lightroom, and DxO. I've also had plenty of crashes. So much so I ended up building a PC, but that's another story.
A couple issues I've had with my Vaio:
The AMD GPU doesn't play nice with PS. That's what crashes it. Sometimes it's worse than others, but it definitely "flares up" at times and even the simplest of operations will crash it. I've tried all kinds of updates, and rolling back drivers and whatnot. None of it works. Turning off graphics acceleration might of helped, or it might have been placebo. My main solution is to save often and completely close and reopen PS in-between major projects.
There absolutely is an issue where PS doesn't clear out the ram when I close a big document (I frequently work on projects in the 2 - 3 gB range). I also did a lot of research on that, and many swear that it's how it's supposed to function, but mine gets so bogged down it can't even open a small photo. It doesn't do it consistently, but when it does it's obvious that something is wrong. My solution is to simply close and reopen PS.
All Windows computers, in my experience, slow down after a few years. Task and registry cleaners only work so much (and are supposed to be unnecessary in Windows 7). People attribute it to the computer being old, but if you simply (ok not simply) wipe your drive and reinstall Windows and your programs it suddenly works like new again. I had to do this to my Vaio a month ago after my hard drive crashed. I also upgraded to an SSD. It was a pain in the ***, and took a whole night of loading programs and tweaking things back to how I had it, but it runs better than it ever has. Knock on wood - Photoshop has been running a lot better too.