After 15 - 30 min slows down

[Patte6]

Hello @ All.

Since one week, i try to find out why my Dolphin slows down after 15, up to 30 Minutes.

Matter what settings, its everytime and with every game. No FrameLimiter, no external Framebuffer.

I play on Notebook for example New SMB and it runs perfectly (constant 60fps). No Laggs, Nothing.
But suddenly Dolphin slows down to 30 fps and nothing to do for up-speeding. Also i restart the emulator and i can play again for 30 minutes.
I searched fixes or special settings for this problem here in the Forum and elsewhere (GOOGLE).
Tody i've checked Turboboost, to be overheatet. But that isn't the reason, because my CPU constant (with turboboost) stay on 2,96 Ghz per core even the game runs slowly.

Specification:
Acer Notebook
4GB DDR 3 - 1333Mhz
Geforce GT 420M 1GB
Intel Core i5 560

My idea is, the GPU RAM runs full or other cachings runs up to limit, but dont can underpin this idea.

I've Tested many Settings (openGL, directX, no EFB, no audio throtting, and so on...)

thanks in advance.

[HawaiianPunch]

Download Realtemp and watch the temperature. Your laptop is overheating. Instead of looking at clock speed look at temperature.