Not to be rude, but if you don't understand the difference between these CPU's, you are missing the fundamentals. Perhaps you could try doing a bit of research into what the terms mean. I highly recommend Tom's Hardware. They have been around FOREVER and have some very informative pages on CPU's, graphics cards, memory, etc. As for your questions... L3 cache - the 3rd layer of cache on a CPU. A bigger number is better.Operating Frequency - the frequency the CPU runs at. This is a factor in how fast the processor is. Bigger is better, but the multiplier and voltage also factor into the actual speed of the processor.Dual/Quad core - the number of cores is basically a measure of how many CPU's you have. Back in the day, you would have multiple CPU's if you wanted more processing power on a server. Today, there are OS's and enough applications that can take advantage of multiple processors, so it's generally better to have a larger number of cores. HOWEVER, if you aren't going to use any applications that can use 2 or more CPU's, you will be wasting your money (to some degree).Sounds like you need to do a bit more reading, but that should get you started.