What is the difference between Pentium D and Core to Duo

This is not me talking because I am very technically challenged!LOl However, my hubby is not and I asked him to answer this...so here goes: In theory..Duo Core is faster than a Pentium D. However, what you have to remember is that your computer is only as fast as your slowest compenent. ie: If you do not have a lot of memory (1-2 gig) your computer will be slower no matter what processor you put in. If you are a gamer and you put a cheap video card in...games will be slow or not work at all. If you put a slow hard drive it will slow the computer down as well. So basically it is not just the CPU...you need to look at all the compenents that are inside your computer. Hope this answers your question.