well in many cases celerons are pentiums that didn't come out quite right in the manufacturing process, like there were certain problems with the chip when it was finished being manufactured. SO what Intel does is they close whatever pathways on the would-be pentium that don't work correctly and rebadge it a celeron. This isn't anything out of the ordinary, AMD does it too and so do video card manufacturers. But the point is, when you get a ceeron, it is inherently inferior to a pentium and will likely not work as efficiently, whether its worth the money really depends on what you're going to be using it for. I'd say if you use your computer for more than just word processing, media, and internet, go with a pentium