Lag issues

[Wanted]

Well everygame i join i lag the odd thing is if i make the lobby in officials servers or best available i dont but if rejoin the same game i made i lag badly again so if some one had an error like this before and solved the problem ill be in ur debt if u tell me how to fix it.

This didnt happend before, started like 4-6 months ago, yes all internet apps are closed, yes i have a wifi router yet ive checked and is the only machine on, updated antivirus aka no virus etc.

Yes ive tried with mods, without mods, my pc is I5 2500k, 670 gtx, 6 gb ddr3