Presario V3758TU laptop, dual cores randomly drop from 2.2ghz to 1.5ghz

I bought this Presario V3700 series laptop earlier this year (around February), and recently, I find that the laptop will have random frame drops (I play a 3D game at a smooth 35+fps, then it suddenly drops to 10~15fps every 40 seconds or so). Eventually, I opened up CPU-Z while playing the game in windowed mode, and notice that whenever the said frame rate drops happen, both the core processors will drop from 2.2ghz to 1.5ghz. Anyone knows how do I fix this (is there a way to force the processor to run at 2.2ghz all the time?)?

I've done the obvious things, like downloading and installing the latest X3100 graphic card driver, setting the power scheme to "always on", turning off every other background applications, and even shutting down my anti-virus while playing games on it, but the problem persist (and oddly, it doesn't happen to 2D games, so I can play MAME or any emulated games smoothly without any problems).

Here's the laptop's specs if it helps:
T7500 Core 2 Duo, 2.2ghz, 2gig RAM, Intel X3100 graphic card

 

Updated and scanned with Spybot Search and Destroy, none found

 

Check your temperatures using HWMonitor. Post back with your temps.

Its might be downclocking due to overheating.

 

Dear lord, this can't be happening! I'm using a laptop cooler too.

 

Your fans are most likely clogged with dust, thats all.

Check your service manual on how to clean it.

 

Wow, was that at idle? Do you blow out your vents regularly to keep them clean of dust?

 

Idle or not thats still way too high

Please see the NBR cooling central

 

Thanks, guys, here's the new temperatures at idle:


I just took those hand-pump air blower thingies (they don't sell compressed air/canned air over here in Malaysia, so this is the best I could do) and blew air into the fan exhaust and the part where it takes in the air (while the laptop is operating. I figured out that with the fan still turning, it'll blow out the dusts that were removed). Dear lord,there's so much dust coming out, I can't believe it (though I can hardly make the air reach the fan itself, thanks to the tiny air input duct , unless I disassemble the laptop casing, which I don't dare to do at the moment. I bet the fan have a layer of dust on its blades too)

Thanks once again

 

and here's the temperature in the middle of a game. Is it still too high? What's the normal temperature range I should get for a laptop with similar specs as mine?

 

Usually 5-10c cooler than that for both idle and load.

I guess you didnt get everything but did get rid of quite alot. Best way to clean the fans is to open it up and use a toothbrush or q-tip to scrub them off the blades directly.