Vader, you could try increasing the priority of minecraft in Task Manager.
Which will give it more resources, so it should work better.
Try adjusting your setting to lower graphics, or install this mod:
http://www.minecraftforum.net/topic/2496...fps-boost/
If you can't, or don't know how to install it, here is the modified jar for you:
http://www.mediafire.com/?fjrpq9s6d06vf00
Replace that with you jar in your .minecraft folder, you will need to enable hidden files to get to said directory.
C:\Users\<Your User>\AppData\Roaming\.minecraft\bin