The Pentium. No doubt based on the other factors like cache & other technical stuff. The small difference in processor speed is not nearly enough to compensate for the superiority of the Pentium over Celeron's architecture.

Depending on the generation and assuming we are talking of chips produced during the same time period. In this case, the P4 2.8 and Celeron D are both based on the Netburst architecture. Both chips are produced on the same wafer and production line. Both chips are 99% identical. The main difference is during final testing and validation, the Celeron had a small deformation in a portion of it's cache. So Intel disabled half of the cache (Including the malformation) leaving a perfectly functional other half enabled. The Celeron is 100% ok to use and there is nothing wrong with it, nor will it cause any data problems. If it were not for a bad transistor in an area of the cache that Celeron would have become a Pentium. Which one is better depends on what you do. If you plan on gaming, the slightly faster Celeron will be the better choice. If you plan on doing encoding work like Video, "LOTS" of MP3 ripping (or converting), Winzip/Compressed Archiving, then the extra cache despite the slightly slower speed will be more beneficial to you. Chances are you are a gamer, go with the Celeron. It's also half the price of the P4 2.8. EDIT: Why you wish to choose a Netburst chip sort of puzzles me. MHz are not a real way to measure the true speed of a CPU. For the same price or even less you can get a much faster chip using Intel's much improved Core Architecture. The E2200 and E2220 are with in the same price range as the P4 2.8 but are nearly twice as fast. http://www.newegg.com/Product/Product.aspx?Item=N82E16819116070 http://www.newegg.com/Product/Product.aspx?Item=N82E16819116063