Simple methods that MIGHT help you boost performance.

[HailNKill]

1- Set high performance from power options.

2-Set client.exe to high priority from task manager when ur in game.

3-This game doesnt actually run in true full screen,you might try pressing alt+enter AT THE EXACT same time to enter full screen(might need few tries but dont give up) which might help.

4- If you use Nvidia graphics card, go here:  

 

https://www.youtube.com/watch?v=zlcCB3eyV-s

5-Sadly there are not many options for AMD users but this works for some people so might worth a try:
https://www.reddit.com/r/bladeandsoul/comments/45mapg/for_amd_users_with_poor_performance_and_high_end

NOTE: These are just basic stuff u can find from the internet by an easy google search so,i'm just collecting all here for lazy people.

6- Last and imo only one worth a shot:
   Unparking cores.

Here is a quick guide on how to do it,it's nothing dangerous and has a chance of increasing performance especially for windows 7 users.
 

https://www.youtube.com/watch?v=4fKxZ1mq9KA

PS: If it says parked on some or all cores even after you unpark them , at registry key keep pressing find next and set all value max/mins to 0. (you'll see registry stuff in youtube video)

I know most of these are known stuff.
Was bored and just felt like making this,maybe works for some people.