ok so we have a couple of "fixes" now:
disable the water effect
removing the emotions of the faces
running the game on virtual pc with windows xp
and a couple of other suggestions

we can now add to this list downgrading to nvidia driver (if you have nvidia ofcourse) 186.18.
yes it fixed the lag for me.
but do I like this fix? nope, the graphics did not improve with the downgrade and fallout new vegas is not the only game I am playing.

but maybe this solution is something for you, but I am gonna wait for a proper update I did not spend 50 bucks to play a laggy game.

Well, the 186.18 version didn't work for me, same low fps with NPCs. I have a Q9550 and a GTX260 on Win7 x64.

o for comparison, I have amd phenom II x4 @ 3.6 win7 and gtx 295

but every computer reacts different to the fixes listed above, which does not sound that strange but I find it really weird. and that also means that the patch has to cover a LOT of issues

My theory is that most users, more or less, are having the same problem. Most, if not all, are nVidia video card owners, which strongly suggests a driver issue.

Many people have posted that only up to 30% of their graphics card is being used during the game, even when the framerate drops. I would be willing to bet that we are all experiencing this. 30% video card power may be enough to render the environment without slowdown, but the NPCs, special effects, etc. ramp up the power needed, and hence we get the drop in frames.

Now I don't know about you, but I didn't pay $400+ for a graphics card only to have it use 30% max in a popular, just released game. Bethesda/Obsidian had to know about this before release. How could they possibly not know? They're just counting on people just dealing with it (which most of the community does, those that come here and complain about the issues are few and far between from the whole).

The 30% maximum ultilization of the nvidia video cards is the real problem, and that is why all your little "fixes" (read: graphics card tweaks) are helping. We shouldn't have to compromise like this. Fix this, Obsidian/Nvidia.

You do understand that now they are celebrating, drinking a lot of beer, vodka, dancing with girl, not everyday you release a game, it will take weeks for making the patch

@mwelling12
agreed

ye im sure it will take a couple of weeks, pfff maybe I should just buy it on 360, I prefer mouse play you know and it seems a bit weird to have 2 copies of the game.
but having to wait a couple of weeks while I have a lot of time to spare this week, svcks

Resist the urge man! lol. IMO I wouldn't give them the benefit of a second purchase, especially the same game.
I'll wait for a patch to be released and if the issue is never fixed then oh well.
I had been on the fence about this company for a while, I like the open world styled games they produced but hated their bugs, and I was hoping this
game would have been the one to wait for.

It might be a great game but I'll never know until these problems get ironed out and that's the problem.
It seems more and more companies are following this practice lately, for that matter I think bioware is the only one that I
haven't been burnt buy yet.