Guild Wars 2

Notebook gamer here.
I have switchable graphics (Intel HD4400 and an AMD HD 8850M GDDR5)
As others, I too used to have 50-60 fps, but something happened. First I have noticed these fps drops when I was in Divinity’s Reach looking in the “Upper City” direction from Dwayna high road.
But it is in the Mists, in some PvE areas and in almost every city.
The funny thing is that I have more fps with my Intel with the same settings applied.
What have I tried so far:
-Because it is a notebook, obviously no hardware changes;
-Every other 3D applications are as good as they were;
-Driver update/downgrade;
-Different graphics settings;
-Other people’s guides like deleting files form: $USER$\AppData\Roaming\;

A friend of mine reinstalled his notebook because “Every problem can be solved with a Windows re-install” as he says and guess what. Now he has 35-40-45 fps with a GT 635M on medium settings.

Now what?

Greetings everyone!
As the title says, I am experiencing fps drops at some places in the game (19-25fps). To be more specific in some areas looking in a certain direction, or looking at something.
For example: in Destiny’s Reach when looking at “The Upper City” direction from “Dwayna High Road” (as you can see in the attached screenshots).

I have a Dell Inspiron 3537 with the following hardware:
CPU: Intel i7-4500U;
RAM: 8GB LPDDR3 1600MHz;
VGA: Intel HD4400 and AMD Radeon HD 8850M GDDR5
OS: Win7 Home Premium SP1 x64

I would not make a sound if I didn’t know my notebook was a beast, so lets see what we know for now.
-When I run the game with the Intel HD4400 I have more stable/smoother frames, but of course only at these places. The produced avg. framerate is still lower than with the dedicated card, but at least the framerate won’t drop under 30fps, with the appropriate graphics settings.
-When I set the settings to “Best appearance” using the dedicated vga, I still won’t have more than 25fps at the mentioned places.
-Every software/driver is the latest (not beta) version and the catalyst settings are set to the default parameters (did lots of tests with different ‘forced settings’, did not help)
-Was not always like this. I mean, I suspect a not too old graphics enhancement patch that causes nuisances like this, mainly because the two graphics adapters react differently.

Any thoughts anyone?