my computer keeps showing CPU at max.
Answers (2)
The answer is neither and both but speed of a PC is determined by both RAM and CPU. Depends on what you will be using the PC for. To have a processor with high speed is good but you might not see any difference with increase in processor speed when using normal applications on your PC, but try using the same PC for gaming or Graphics design and then it'll pay to have higher processor speed.
The real answer depends on how much you have to spend on your new computer and what the base system is. If the base system is at least 2 Ghz then I would apply the money towards memory, otherwise I would increase it to over 2 Ghz. If you have money left over I would spend the rest of your budget to increase your memory to 4 GB or as close as you can get. These days, you really should have at a bare minimum of 2 GB of memory, with 4 GB being preferred.