Pentium® D 820 or Pentium® D 830?

It would be worth it to consider Athlon64 x2 if dual-core is really the way you want to go...

My only option at the moment is Intel CPUs with the models mentioned...

Hmm... For cheap, the 820 can't be beat (even by the AMD). But I would buy the 830 for the extra speed. Not so much today (not too much difference in performance, really), but in a couple years that 200mhz may make the difference between adequate and dog slow. (sounds strange, but that is the impression I get with my old 850mhz AMD compared to my old 1000mhz AMD - the 850 is just enough slower)

Mike.