6935g CPU problems.

I've just noticed some games drop framerate that worked fine a few months ago. So I tested another game shadow of memories which is pretty old plus running at 800x600 and after a couple mins of running about i drop from 30 to 24-28 and fraps drops that even more while on my XP partition i get smooth 30 even recording with fraps. I've tried running Rmclock but i can't tell if its throttling and the game doesnt minimize. The temps are normal at around 50c while playing too and my bios are updated.

Was going to leave it and thought it was just Vista but i ran 3d mark 06 and compared my scores to before and its gone from 2400+ cpu to 1500. I dont have epower so use power options in control panal. Set to high performance and cpu set to 100%.

Other games don't seem as bad like chaos legion but i haven't got anything modern atm installed to test. Beyond good and evil seems to go at 50fps but it doesnt suddenly drop like shadow of memories. I would of thought it was just vista if the 3d mark results weren't so low.

I've never seen this problem with the acer model i have D: Its the 9600m 512mb, 2.53ghz version.

Anything i can try? thanks.


EDIT - I just found out something weird. I play shadow of memories and when the framerate starts struggling I plug in my external HDD and it runs perfect for about a minute. Better than it did before and i can capture 60fps without any slowdown. Yet after a minute it all goes down to 20fps when capturing and 24-28 when im not.