I gets 10 - 20 fps even on minimal settings…
Please give me any ideas to improve my fps
or should i have to change computer?
Also you can vote what is your FPS here
https://goo.gl/dLYf65
How to improve my FPS?
Salt_N_Pepper
(Salt_N_Pepper)
#1
Kirays
#2
Hello.
What are your specs?
You probably need an upgrade.
Be aware that Dirty Bomb is built on the Unreal Engine 3 hence you need a strong CPU to experience good performance.
Try out the steps I have described in the spoiler below, they might help you. 
[spoiler]First of all, open the console by pressing ~ and type in texturepoolsize 1.
Do that in the main game menu to have it take effect the next match you play.
Furthermore you can lower the ScreenPercentage number in the ShooterEngine file.
[spoiler]http://i.imgur.com/lbGOxEg.jpg
[/spoiler]
To make it look like the above screenshot, change it to 50.000000
You can even go lower but I do not recommend that.
There is also the possibility to create an autoexecution file that loads commands like the texturepoolsize one every time you start Dirty Bomb.
The user hypnotoad explained it in this thread.