I can tell because there is massive screen tearing / its looks like a slideshow (don’t think I can go back to 60hz now!
). I also have a small tv that i use as a second monitor which I opened up the nvidia control panel on - to see what the game was changing the screen setting to, and it kept going back to 60hz.
I have the Asus VG248QE which has the lightboost stuff. I installed the driver and registry hacks for enabling the 3d without the glasses for quakelive - its awesome! 
[QUOTE=woll3;450092]MinAllowableRefreshRate=120
MaxAllowableRefreshRate=120[/QUOTE]
Thanks, yeah I tried these from the other thread - it seems that provided I run DB at the same resolution as my desktop that the 144hz will remain on. But if DB has to change to a new resolution when it launches it will choose to go to 60hz.
I tend to run my desktop resolution at just below the native (yes everything is slightly blurred) because its easier on my eyes - but I use the native whenever I am playing games. Think I am surely in the minority who does this so perhaps most people wont experience this problem with DB