Slow Change Weapons

Hi, i buy a new computer (much better than my first one) and a router, I enter the game normally, but after i joining any match, and i press to change for any weapon, it take a long time, i don't know if this is network issue, but i played better in my first and bad computer...someone says why?

AND...sometimes when i join an room, the mouse freeze and computer, havind to restarting the PC.

Please, someone help!!