Yes, when playing online turn the settings down a bit, or you WILL lag. And trust when I say that's no fun.
Although you should be able to play at medium settings, I did encounter a few spots wherethe game lagged for a bit. To easily solve this issue just open the menu, select your Settings. Change them down to Low, hen select OK and it will rebind the textures and you'll be lag free. Then once out of the "lag zone" go back and turn the settings up.