Processor on dell inspiron 1525?

If you're just surfing the web and checking email, then any of these will do, and you probably would not notice any difference. If you download movies all the time, and/or play 3D games, then you want the fastest one you can get. As for the fsb (front side bus) and the cache, the higher numbers mean faster processing. The fsb is basically part of the connection between the processor and the rest of the pc (hard drive is a good example). If you have a fast cpu (brain) but the connection to other parts is slow, then the brain is always waiting to hear back from the other parts before it can continue processing. The cache is just another kind of memory just for the processor, and the larger it is, the more "memories" it can hold. Commonly used "instuctions" and locations can be kept, which will speed up processing.