Low end-gear trying to boost

Hi guys!

I'm playing CoH2 for a couple of months now on a low end gear laptop.
My specs:

- Windows 7
- Intel(R) Core(TM) i5-3230M CPU @ 2.60GHz

When I started playing the first day I had some lag, so I tried to find some solutions. And I have found some, now the game is playing very smooth.

Some stuff I have already done:

- Disable replay recording
- Change some stuff in the config file

Im very happy with the result it gave. But now I was thinking to change my resolution to the lowest in the game. 800 x 600. My desktop is on 1600 x 900. When I change the resolution I get two black stripes on my screen. And the game is in the middle of it. Is there any way to make the game run full screen in 800 x 600? This worked fine in CoH1. Does this need some work to in the config file, or is this simply not possible? Wich wouldn't be a big problem, I'd just like to test it out if it would make a big difference in performance.

So my question: How can I use the resoltion 800 x 600 without those two annoying black stripes on the top and below.

Thanks in advance!

Edit
Things I tried so far:
- Add -refresh 60 to launch options in Steam.
- Change desktop resolution and switch to scale to full size.