Title says it all.
There's 3 different types:
First is where most hud elements disappear, dying in pvp shows nothing- no gun, inventory doesn't load, etc. In game hud such as abilities stays. After the activity, going to orbit instantly freezes.
Second is, I assume, tabbing out, then the game freezes in background.
Third is the game just freezing generally.
Either the latest patch or latest nvidia drivers.