Help! FPS drop every 10 seconds on multiplayer servers!

Basically, I load into any given MP server and after about 5-10 seconds I get a major fps drop. This happens constantly and is very frustrating. I just got an R9 270 radeon card that has been good so far except Arma 2. I reinstalled the drivers and have done that twice now.

THIS DOES NOT HAPPEN IN SINGLEPLAYER!

I have tried changing the documents, and my graphic settings ect with no success. I don't know what to try anymore.

Please help :(

What kind of servers?

Where are they located?

Your ping on them?

Does this happends on all servers you tried?

How many you tried?

What is your internet connection Download and upload speed? (Friend of mine was constantly complaining about lagging in multiplayer, on server we all had more than 30FPS so we asked him what is his internet speed, he has cheap ass up to 2Mb shared WIFI internet. so no wonder he lags.)

I know from experience, that most of the servers are laggy for me. Finding server with good FPS is hard i spent lot of frustrating time finding playable servers.

I have wery good experience with German ACE/ACRE coop servers (DOMINATION, PATROLL OPS) 20-50FPS. Except TF47.de. I get around 10-15FPS on that one, wich is bad. Also some Wasteland servers are ok if not too much players on htem, and DAYZ servers in general 25-50FPS wich is great. Really bad experience with Russian servers and American servers (maybe because of the distance).