What you have there is a netburst architecture CPU that was mediocre when it was released... nearly 10 years ago.
Don't expect much.
There's no point in trying to upgrade it. If you run across a rare Paxville DP for dirt cheap (like $20) it might be interesting to see if it will work in the workstation, but the performance is still going to be from an entirely different erra of computing.
Perspective:
A modern dual core Celeron, is about 6X faster than the Irwindale Xeon in that workstation.