I am trying to record midi drums with Sonar X3e 64.
 
Here's the setup:
 
Samsung laptop, i7, ssd 240gb, 6 gig ram
Focusrite 2i4 interface
Korg Nanopad USB midi controller
 
Korg is plugged to a USB port of the laptop and Focusrite to another (i have also tested the internal soundcard using Asio4All).
 
When I try to record drums using addictive drums or other soft synth drums I get an odd feeling that the metronome "starts to wander" so that it is extremely hard to follow it.
 
I am in no way a drummer, but usually have had it quite easy to follow a tempo. This just makes me think if im insane or something.. Has anyone else experienced the same? Any help?

Mine has always seemed metronomic,  my keyboard on the other hand does play several bum-notes. 
 
Seriously though I doubt that the metronome isn't accurate although if using an external synth for the sound I guess there could be timing issues there.
 
The other thing to check is that there aren't any tempo changes in the project.

Just make sure you have bypassed/disabled any plug ins that are known to cause latency. 
 
The only reason the metronome could wander is because you told it to. Check your tempo map. 

You could add a simple 16th loop or even an AD midi pattern, then record over that. Might be easier to tell. Or try to record just the metronome on your phone and import the wav to check. I have had this once with Ableton and it drove me completely bonkers. Turned out to be a very uncommon but known bug, a reboot fixed it.

Just the other day I noticed that the metronome was getting off by a whole beat during loop recording on a particular project. Have not noticed it getting off other than that.