Ok, so the story goes...
Got vista (ultimate, x64), combined with halo and a few drivers. got my pc working comfortably. one month's hassle free gaming and now this...
when i log on, or play campaign, it works fine. but online gaming allows 5 second bursts of movement. even on low ping servers. as i said, i had been playing for about a month, on my usual servers, and it worked fine.
i tried the normal things; defrag, update graphics drivers, reduce resolution, kill background tasks, check router/ports/wireless; heck i even cleaned my pc physically.

And still nothing.
as the title says, vista has been ticking away, updating itself. oh and i ran through firewall and defender, they're kooky [ok] too.

god i miss halo.

somebody help!

here's my dx diag stuff anyway.

cheers!

try disabling auto update and/or uninstall most recent updates

I am up to my neck in frustration... Your problem with halo is identical to mine.. Ive spent the last two days trying to fix this issue.. I tried all the steps you did plus reformated my hard drive to factory out of the box state, which means that windows updates probably didnt have much to do with it.. considering Halo was the first thing I tried after a fresh copy of Vista..If you have any breakthroughs or thoughts please lemme know... Ill do the same... Im not givin up yet

-steele