pentium? sounds slow =p
modern chips are all pretty fast, it is simply a matter of features.
My work PC recently kicked the bucket, and I replaced it (was a core2quad) with a lowly ivy bridge Pentium G processor and could not be happier with it (as an office PC anyways). What makes Pentiums feel slow is not the CPU itself, but all of the other supporting hardware. I paired mine with 4GB of DDR 1600, a SSD, and a $50 GPU for proper multi monitor support (610 or 620), and everything runs great.
Take that same CPU and put it in a system with 2GB of ram, a cheap HDD, and rely on onboard video and ya, that would be one frustrating machine to use... but it has nothing to do with the processor.
For office work, which is what that machine is built for, it is just as fast as my wife's i3 or my i7 system at home. Playing games it would probably not hold up too well, and doing post production it would simply crawl, but it dosn't need to do any of that stuff. For browsing the web and doing office work then instant is simply instant, and there is no perceptible improvement across the board going all the way from a Pentium up to a 6 core i7.