Hello,
Thank you for reporting the issue.
We need rpt file from this folder for solve your problem.
C:\Users\<Name>\AppData\Local\Arma 3\
Can you upload somewhere in winrar package please?
When package will be smaller than 5000k, you can attach it here. When package is bigger, please use some free sharing service and post link here.

Thank you.

Sorry it took so long to answer, I was busy the last few days.
Here's the winrarpackage of my C:\Users\<Name>\AppData\Local\Arma 3\

https://dl.dropboxusercontent.com/u/60854868/Arma%203.rar

Hello,
thank you for the files uploaded. Sadly, there is nothing suggesting any failure in them.
Please try to create new profile ingame.

Could you please verify that this still happens in current version 1.16 and if it does, verify your Steam files?

Here is a hint how to do that, thank you:
https://support.steampowered.com/kb_article.php?ref=2037-QEUH-3335

Hi,
it will take a few days to do that since I can't access my computer right now.
Standby for updates.
And thanks for the help so far! :)

Your CPU is lacking in speed, 3GHz is rather low.

Try putting:

shadows on standard/high (NOT low)
objects to standard/low
view distance < 1500

If playing MP, try different servers.

It seems like it strongly depends on the server. I still have low FPS in MP, depending on the server I'm playing on.

Hello,
it really seems that the performance of the server you're playing on is dependent on your CPU performance. Some servers are very performance demanding so it is difficult for less powerful CPUs to handle them.

Thank you.