Funny thing, it's not exactly lag. Players that seem to lag extremely for you, may not lag at all for others. I can only guess it's a desynchronization issue between clients.
I know exactly what you're talking about. My suite mate has this problem.
We've tried so far: Him playing on his own connection, me on mine, both wired directly to respective modems. He's the only one in a public game who warps all over the place (ON MY SCREEN). On his screen EVERYONE is warping all over the place.
Both of us wired to my connection. He is still the only one that warps everywhere on my screen, everyone warps on his screen.
Both of us wired to his connection, same thing.
Clearly this isn't a connection issue. Maybe there's some sort of hardware conflict or bad drivers. I got him to update all of his drivers but still the same problem persists. The only thing that seemed to help a LITTLE bit was uninstalling Hamachi from his computer. I'm not quite sure how that would help though.
My system:
p8p67 pro
i5 2500k @ 4.4
580 GTX DC II
8gb ram @ 2133
9mbit connection
His system: (unsure on most of it)
GA-970A-D3 Rev 1.4
Phenom II 6 core @ 3.2
AMD Radeon HD 7700 (I think)
16gb ram @ ?
1gigabit fios
