That's a business desktop, and quite a old one. At least 2/3 years old at a guess. Some problems I foresee :
The mobo is (I think) probably limited to the speed that it already has RAM wise. So you will wasting money on faster sticks. In fact I've read that the actually chipset might only support 1066, guess HP just stick the higher speeds in for the fact it looks quicker. The crucial memory checker seems to agree with me.
http://www.crucial.com/uk/store/list...itower&Cat=RAM
Other issues :
As a business machines it's fairly limited and I believe that you may issues with high end graphics cards, I doubt the PSU has the extra plugs or you use adapters it won't be up to the job, they assign the bare minimums.
Also you won't be able to upgrade the PSU as the HP mobo I think has a proprietary power feed.
The graphics card compatibilities are quite bad as well, HP only test a handful of Quadro style cards and quite often normal cards just don't work.