Thanks for the replies. The basic problem was that Photoshop took a bunch of memory and never seemed to give it back, even when the large files were closed. The machine gradually slows to a crawl with spinning beachballs. Looking at activity monitor shows decreasing amounts of free memory until it would get down to 10-15MB, that's MB, not GB, and be soooo slow that I'd need to quite PS and or LR, restart them to get things going again. Memory for this machine is expensive, OWC charges $640US for an additional 24GB of RAM. That's before adding an SSD, which I know would speed things up.
I suspect there is not a simple fix, short of a new machine. It is over 5 years old, will be 6 this September, so I guess I've gotten my money's worth. The problem, of course is that the new Mac Pro is a new paradigm, a completely different way of organizing one's information. I've enjoyed having my main photo drive (4 TB with 50k images) and back up drives within the computer, out of sight but usable. With the nMP one needs to have a separate Thunderbolt box for the same functionality. All of this, plus the non-trivial cost of the machine, (even a "lowly" quad core, 32GB of RAM, at least 512GB of PCIE based flash storage, $3,800 and Lloyd Chambers recommend a 6 core for an additional $500), really adds up.
Best to all.
Yeah, tough to sink money into those old machines. You could throw 4 7200 rpm drives as a RAID 0, install a PCI SSD drive for boot up, throw in 32 gigs of ram, and it may help a ton.
But I agree with the previous post, something seems to be wrong because even the 2006 and 2007 Mac Pros i recently replaced with Mac Minis in my shop were still very functional, running PS CC and LR 5 all day long. rebooting was usually a weekly thing, only because we shut the machines down on Saturday and start them up again on Monday.
You could have issues with your Hard drive, a ram module that is a little flakey. You may also have to be paging into virtual memory more than you realize this (you can monitor your VM load and page ins/outs in the activity monitor. You may want to back up everything, re-install the OS and applications for scratch.
My last Mac Pro purchase before this month was the 2010, but looking back Iím into this new mac pro far less. Considering the dual graphic cards and blazing fast SSD, I think itís the most reasonably priced Mac Pro Apple has made (just expensive compared to all of the other macs). As far as having the drives tucked away inside, thatís what I used to think until I put everything 10 feet away with Thunderbolt. I can also mount all that drive space immediately on my MacBook Pro, or any other computer. Iím fully converted, modular is far better. No need to overbuild the power and cooling of a tower. The only reason drives needed to be internal was internal bus speed, TB changes all that.