I doubt the issue is related to ur HDD. Hard drives generally only operate in a game when something (like a level) is being loaded. during gameplay hard drives have almost no impact in frame rate (if any at all!).
There are a couple things to consider here:
1. are you playing the game on battery power? if so, CPU speed and GPU speeds are dramatically reduced when on battery power. hence you will get bad performance.
2. drivers. i would suggest going to ATI's website and downloading the latest catalyst drivers. OEM's often ship the "most compatible" and "older" versions of their own drivers. performance can be dramatically increased using catalyst drivers.
3. Mobility radeon x600 GPU- certainly it's no slug, but it's not exactly the fastest either. if you're trying to play this game at high resolutions with max settings, frame rates will be slow. go into CC Generals setup/options and try laxing up some of the settings like texture, anistropic filtering, and FSAA.
Hope this helps...
-mpjesse