processor.

Mhz -

  This is the overall speed of the processor. It used to be that it meant nearly everything! Nowadays, things are vastly different. I just bought a brand new computer that is 2.4Ghz, replacing one that was 3.0GHz. It was really tough to do - for me, it was counterintuitive. The way I explain it is this; think of a highway. The MHz is the speed at which the cars travel, and the Bus Speed is the number of lanes there are. Basically, MHz is how fast the data can be processed, and BUS Speed is how much data can be processed at once.

Bus Speed - 

This refers to how much data can move across a "bus" at one time. In simple terms, it refers to the amount of data that can be processed at one time. This is the primary reason a processor with a lower Mhz can still out perform one with higher MHz, if it has a higher bus speed. In most cases Bus speed is just as important (if not more so) than the overall speed of the processor. You will also see this term used on motherboards, as well as RAM, so whenever you are replacing a CPU, it is important to make sure your motherboard can support the new CPU's bus speed.

Cache -

 This is what the computer uses to reduce the amount of time needed to access memory. In simple terms, the more cache your processor has, the quicker things can happen. There are also several different levels of cache - when you are looking at a CPU, it will look something like L1 L2 or L3 cache. These are used for different things, and most computers now have different cache for instruction, data, and translation. It isn't as important that you understand specifically what each of them do; rather, it is more important that you understand they are there, and that different levels of each will affect your processor's performance.

Cores -

 This is something to come about pretty recently, and can be very confusing. The most basic way to look at it is that a multi-core processor means having identical processors, dual core being two and quad core being 4. This raises issue with some people, since the argument is that a dual core 2Ghz processor should perform as good as a single core 4GHz processor. This isn't always true, especially if the software you are using cannot properly make use of the multiple core environments. That said, in general terms dual core is better than core 2, and quad core is better than all of them. For most people, it doesn't really matter - but if you use your computer a lot and for processor intense things, it does.

These are most of the major aspects when it comes to processors. Remember, as you move up cores or speed, you also make drastic jumps in price. Often times, it is better to go for the performance than save the cash - I have always found it better to have it and not need it, than need it and not have it. That said, budgetary restraints don’t always make that possible.