Have you been looking at task manager? If not do so.
It doesn't sound odd though. I would guess that you have a quad core AMD or a dual-core Intel. As each of these numbers would represent a single core being in use. An application that is single-threaded and cannot use multi-cores will peak at 25% when running full speed on a 4 core system. I hope that you see what I'm trying to say. So, if you had two applications that were single-threaded apps running at 100% cpu that would show up as 50% of your CPU.
If you had a 6-core AMD, and if you had one application running full out you would be seeing the numbers 16%,33%, 49, 66%, etc.
This is nothing to do with your hardware. If you look at task manager you can get an idea of what is running. For more information you can download from Microsoft their "Process Explorer" application.
i have a quad core i5 intel 2300 @ 2.80Ghz... and yes i have been using task manager to check CPU load.
it seems all the cores are at some level of load, especially the 2nd and 4th.