CPU
Some basic terminology, in case you're curious:
Cores: How many physical "centers" of thinking are available on your CPU.
Threads: How many logical "centers" of thinking are available on your CPU.
Speed: How fast processors go. While these are usually measured in gigahertz (GHz), we've opted to measure them in megahertz (MHz).
Cache: How much memory the processor has on hand. Yes, RAM is also memory for your system, but cache is much faster since the processor has this available right on its chip. The more cache you have, the faster your system generally is.
TDP: Thermal Design Power. This measures how many watts a processor is designed to draw from your power supply. This term also applies to graphics cards. With CPUs, any TDP over 90 watts generally calls for a better cooling solution than what would be otherwise available from the manufacturer.