XPS L521x GPU throttling issues

Hello!

I received a new XPS L521x two weeks ago but I keep having throttling issues with the GPU. The system is running on Windows 7 64-bit, all the latest drivers from the Dell Website, newest BIOS (A14), are used.

Specs are:

CPU: i7-3632QM

RAM: 8 GB

HDD: 32GB SSD + 250GB SSD

GPU: NVIDIA GeForce GT 640M

When I play games I get a very good framerate initially (around 70-100 fps) but then it drops to below 20 fps which makes the game basically unplayable. Then the fps go up again. When I monitor the GPU clock rate on a graph (using EVGA Precision X), I clearly see the reason behind the problem: the clock rate is constantly switching between 645 mhz and 135 mhz, explaining the fps drops.

How can I fix this?? I've been searching the forums and this seems to be a common problem with the L521x. This was a very expensive notebook and I would very much appreciate a solution to my problem. In previous posts there was often the reference to future BIOS updates to fix this issue, but now we are at version A14 and still the problem seems unresolved. How can I stop the GPU throttling?

Thanks for any answers!

Best regards