You mean 7% when gral is not on and when you turn on graal it's 67%???
Lower the rez but to lower the rez you have to play on full screen mode or it wont work. Turn off the special effects but they don't do that much stuff.
System specs?Without them I'm just shooting in the dark :P
Memory and processor and the copy of your OS
If you have low memory your processor will be busy swaping file from your memory to your hard drive.
EDIT: may might will help if you need to know some things about your memory and processor Go here
http://www.cpuid.com/cpuz.php and download the file
CPU-Z 1.39 the link is around the top left part it will show you your processor and other stuff you need to know.
Or you can get a video card but if you have low memory your video card wont be much help.