I think your problems are likely due to the graphics card (the 7520G is very slow) and maybe due to the CPU, too. KSP is a 32bit Process and is able to use up to 3.6 GB of RAM. Would RAM be a Problem, KSP would crash. FRAPS is a real performance killer. I am not sure what would be the better option in your case. Regarding better hardware, when I am back at home, I can perform some testing and try to determine where KSP needs the most power. Although, I guess other users may have done that already. Searching through the forums might help in this regard.