Which is Pentium 6xx series?

[rizakasela]

Better than Pentium D 820, but not more expensive.
What series?
630, 640, 650, 660, or 670?

 

[stevty2889]

Better at what, you need to be a bit more specific...for progams that aren't SMP aware, all of those you listed are better..for programs that are SMP aware, probably none of them are better..