CS4 Photoshop Performance leaks

Question

Hello,
I have several problems with our business clients and photoshop.
After working on some files, pc or photoshop extremly slows down. So mouse is stopping or moving layers need seconds. Working is not really possible.
We've tried all Adobe Hint, Systemoptimizition, performance tuning in photoshop, with/out opengl, .... clearing profile.
Now we have adobe default settings and problem is still there.
PSD Files about 30MB or 100MB with ~ 60 layers.
Machine configuration:
DELL 7500
-> INTEL XEON X5450 (3.00GHZ, 1333FSB
-> 2 GB RAM
-> HDD: C:\ 2 x 160 GB RAID 0;  D:\ 160 GB
-> 512MB PCIE X16 NVIDIA QUADRO FX 3700
-> Windows XP SP 3, all updates
-> newest DirectX
-> newest graphic driver
-> Windows pagefile -> c:\; photoshop pagefile -> d:\
System is up to date.

Answer 1

wrong, you only "lose" RAM that way when you start hitting the memory allocation limit. It goes like this, windows 32bit can access 4gb of memory, out of that you substract the video card memory and the pagefile and what's left is the maximum amount of RAM that a 32bit windows OS can see, usually around 3.2gb He has only 2gb of ram total so he won't lose RAM unless his video card has more than 1.5gb of memory.
http://kb2.adobe.com/cps/404/kb404439.html
The available RAM shown in the Performance preference automatically
deducts an amount that is reserved for the operating system from the
total RAM in your computer.
In the Performance section of the preferences, it's called Available Memory, not Total System Memory, that's why you see less than 2gb there. Try some of the tips in that Tech Note, see if any of them help. Also, you didn't mention this, do you have the 11.0.1 patch for Photoshop installed?