I discovered over the weekend that having ZoneAlarm Firewall running, seems to make my pings for Vendetta go quite high.
I was experiencing lag at times in sectors 11 and 6, if I disabled ZoneAlarm altogether it ran without lagging.

Is this a known problem?

I am going to re-install ZA to see if it is a local phenomenom!

It may be restricting access to the ports needed to play vendetta. I forget exactly which ones those are, though. I've used zonealarm, and there should be an option to allow unrestricted access to a certain port.

My security software kicks up a fuss with every update, though it is easily resolved by creating a new "rule" each time. Reinstalling may work as ZA will probably prompt you about Vendetta as it configures.

I played under XP *once* and it lagged very badly; ZA was running. I ran Vendetta in windowed mode, so when ZA asked about allowing access I said "Yes, don't ask again". Still lagged *VERY* badly.

OS X, my usual operating system, runs fine. :)

I have XP and Norton, no probs.