oh, lol

no, I got steam version

For starters, you could check current FPS: enable debug, ctrl-d is the key. Not sure if it still works in EE, though.
Alternatively, go back to classic.

Your characters aren't all over their weight limit with what they are carrying are they?

Nope. I just started the game

Try the Steam or Beamdog forums.

It could be a lot of reasons, from drivers to background processes.

You can try the following:

- change in games options to alternate renderer
- find and install latest drivers for the video card
- disable anti-virus
- open task manager and see if there any intensive processes, kill them

I have found the EE stuttering and lagging even on a very performant laptop (i7, 8Gb RAM, SSD) which means it is very un-optimized compared to the originals.