Repeating FPS drops and low GPU usage

After a reinstall of Windows 8.1 POE shows some repeating FPS drops from 60fps (vsync cap) down to 35fps, even if I just stand around in town, doing nothing. This happens every few seconds and stays for a second or too.

The Laptop has an Intel i7, 8GB ram and Geforce 750m.

I checked the CPU and GPU usage and found that, if the FPS drop, the GPU Usage drops, too (70%->45%) (see screenshot).
The CPU Frequency changes, too (130% -> 50%).

One way to get a more constant fps rate is do disable shadows, then CPU Frequency and GPU load stay constant. However, thats really ugly :D

Another strange behaviour: If I run the game on the onboard intel grapics card i have nealy constant 60fps in town with a lot of spikes to lower fps.(however its not playable as the fps drop massivly in combat).

Even more strange: If playing the game on the nvidia gpu, the intel graphics change its frequency, too. (is it coupled to the cpu..?)

Do you have any ideas what causes this strange haviour of POE?

Maybe it's your network. Check https://www.pathofexile.com/forum/view-thread/1377789 and maybe https://www.pathofexile.com/forum/view-thread/305066.

Thanks, but i doubt that its a network problem because i my friends laptop (i7, 8GB, only geforce 650m, but SSD) does not show this behaviour...

Ok, maybe its more network related than i thought.
Both laptops get diffrent latencies. THe problematic one has more spikes and overall higher ping.

I checked on both laptops the route to fra.login.pathofexile.de with WinMRT and the problematic Laptop takes a longer and slower route than the other one. How can that be?!
Both start their route in the same network and thus should be indistinguishable for the internet servers, shouldnt they?