Desktop

You could have a look at Task Manger to see if the Commit Peak is near the Commit Limit. If so then increase the Pagefile (System Icon, Performance Tab).
I would also run Performance Monitor (Administrative Tools) Check the Processor Instances, andsee that both processors are working. Twin processors come into their own if you are running multi-threaded applications. Rendering could be just one thread.

This reads as though you have dealt with a used car salesman,it ain't what you thought it would be.The system sounds good and it probaly is running to peak performance with the info you have provided,One the motherboard has to play a part and the EBis the faster processor ,memory is sufficient,yet you have applications that hogs all it can get,starting with NT,and you have graphics software that will demand memory.your best bet will be to tweek the system until you get close to satisfaction.Good Luck

Another thing to consider is disk fragmentation. I had a simular problem, with simular configuration and 80% resources available, tried everything I could to regain my performance, Norton speedisk and other defragmentation designed for NT. Finallygot it back when I rebuilt the system.

I would also check your programs to see if there is any special settings for dual processor machines. Some programs auto-detect those things and some you have to tell them exactly what you are using. In Photoshop I would go into the settings and see how much ram it is setup to use.

Did you reload NT after you put the second processor in? If not you might check out the MS Knowledge Base article Q142660 (http://support.microsoft.com/support/kb/articles/q142/6/60.asp) "Upgrade from Uni- to Multiprocessor.