Ok i don't know it any1 have same problems, but with nvidia i had huge lags in dugneons and nexus :) so now even on high settings i have no problem with lags. this is my guide (Que) so if you going to post its somewhere else, please don't forget to write where you took it from..
1st step: Download Nvidia inspector From here
and install it.
2nd step: Open nvidia inspector and press Driver settings (two screws), then just type in TERA if they will find tera.exe or tera profile select it and delete.
3rd step: OPEN NVIDIA CONTROL PANEL AND DO STEP BY STEP LIKE IN IMAGES:
4th step: Go to "C:\Program Files (x86)\TERA\Client\S1Game\Config" and delete the following files.
Start your game up so the S1 files get renewed.
Now use the following ini tweaks.
1.) Go to C:\Program Files (x86)\TERA\Client\S1Game\
2.) Make a backup of the S1Engine file.
3.) Open up S1Engine
4.) Press F3 to use the search function to easily find the following lines and change them to the following settings.
Dont change the above line if you have ATI,since i don't know the effects of what will happen with ATI cards,only for Nvidia users.
bDisablePhysXHardwareSupport=True <-----> bDisablePhysXHardwareSupport=False
(Only for Nvidia )
( Your Min - Max FrameRate may be set lower or higher according to what your system is capable of and the fps your have right now.)
Now close the file,rightclick it,select properties and check the box that says Read Only
and do the same for all
other S1 files in that folder so nothing gets changed automatically.