Extreme lag on my machine, lowest settings

I downloaded and tried out the techdemo today and my framerate is just horrendous.
I started out the demo by auto detecting the graphics settings (everything was set to High at this point) and I was getting around 20fps.
I set everything to low (followed the FAQ) and was still getting around 20 fps (even the main menu background is laggy).

This is really strange because I can run GTA IV at over 50 fps on it's lowest settings. RoR runs at over 100fps with one vehicle and max settings.
I messed around in the demo for a while, and I noticed the sign board (the spinning ticker thing) at spawn was running at probably around 50fps, yet the vehicle appeared to be at 20fps.
I must be missing something. The truck is laggy, but the sign board isn't.

If this issue can get sorted out I'll be purchasing the game, it's painstaking to have to drive at such a low framerate.

Hardware:
Intel i5 quad-core @3.1GHz
Nvidia GT520
8GB RAM

- - - Updated - - -

I restarted the game any it is running okay now, this thread can be deleted.

 

Press J while playing and if you get a large FPS increase its most likely your machine not able to handle the physics. (Ctrl + F to check your FPS)

Never mind you figured it out.