MissShoko :
Well, I used to be able to run games and my CPU usage would never hit more than say 70% also my fps was always high around the 60's (This is from looking at the task manager and using fraps to check my FPS)
Now however, when I run memory intensive games, 1.) my fps is in the 20's when it used to be in the 50's and 2.) my CPU usage skyrockets to around 90%
It seems to be getting worse and worse, and I'm not sure what is going on, I just got this computer 2 months ago.
My processor: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz (4 CPUs), ~3.1GHz
My graphics card: NVIDIA GeForce GT 430
The first thing you should do is run "Resource Monitor" and see what programs are running and what programs are using the most of your CPU and RAM/memory. There could be programs running in the background that are not showing up in the bottom right corner or in Task Manager.
If everything appears to be fine there, you should do a "Disk Defrag" next. Your hard drive may or may not be dying on you, for lack of better term.
If everything's fine there, you should then check temperatures. Download a program called "HWMonitor" and run that and check the temperatures of your CPU and hard drive every couple of minutes for about a half hour. Run programs that are hardware intensive as well as let your computer idle, and if your CPU is constantly hot (like I would say 50 to 70 degrees celsius at idle and not dropping) then that could mean that you may have to either apply new thermal paste to the CPU, or get a new CPU cooling system (or both.) If your hard drive is always running hot (like over 50 to 60 degrees celsius) then I would consider replacing your hard drive.
If everything appears to be fine there, then the only other thing I can suggest would be to do a "System Restore" to the last time I thought my computer ran well. You should obviously back up all of your stuff before initiating the system restore to prevent loss of data.
Hope this helps!!