Upgrading to a better processor?

I have an old Dimension 8400 WIth a P4 Prescott@3.0GHz.
I found this processor on eBay, and i an sure it will be a good step-up, I think it will work in my intel i925X chipset.
Link to Xeon:

http://cgi.ebay.com/INTEL-XEON-CPU-3-33Ghz-3-33-Ghz-8MB...

And the specs of current cpu:
Pentium 4 630 Prescott 3.0GHz
Socket 775 LGA
90 nm
Core VID: 1.420V
Bus speed: 200MHz
FSB Speed: 800MHz
Cache:
L1 Data 16KB
L1 Trace 12 Kuops
L2 2MB