Okay!

So my brother and his friend both installed this game yesterday on their computers, and both of them had TERRIBLE lag and stuttering (even though "not that bad computers", sitting on GTX 275 4Gb DDR2 RAM one of them on a Q6600 and one on a 3GHz Dual-Core.. can really remember the name right now, and both of them are on Windows 7 64-bit)

Both of them installed the d3d9.dll fix and the game went smoothly as a childs skin on Ultra settings ... HOWEVER, when they are making a fast 180 turn (or any fast turns thats from 90 and up) They at some point get a huge lag-spike, we haven't found out what it is, everything else are going smoothly as said, and at theese points where it lags, it ONLY lags when going past it at a high speed with the mouse, if you're doing it slow it aint getting any lag.

So my question is, is there some setting to fix this? or is it a well-known graphic-error or something ?

While being at the Mojave Outpost (straight down from the starting point in the bottom of the map) When turning fast to the 2 statues (or if it was the "bow/pillar" at the cars) my brother is getting a hughe lag-spike

Is it rendering lag?

Or HD hitching?

You might want to try to lower the Object & Actor Fade just a bit in the Advanced/View Distance settings to see if that makes any difference.

Beyond that:

As you may or may not be aware, FO:NV, just as FO3 and Oblivion, loads chunks of the gameworld on the fly as you move through it.

You may be experiencing a bit of hitching when you turn, while the HD accesses and loads the new DATA.

If this is the case, some things you can try is:
Defragment the HD. (Preferably moving the game to the outer edge of the HD as well, where it performs the best.
Beyond that, moving the game to a RAID array may help some.
But the optimal solution would be to have the game on a SSD drive. Not all games gain much benefit from a SSD, but games like this that load on the fly certainly do.


Just a thought.

If a SSD or RAID array is not an option, try simply defragmenting.
I have a feeling you may just be experiencing a hitch during a load of new DATA.

I Think its rendering, however not exaclty sure... but both of them have it... dont know myself since I've havent played that much yet.
Lowering the AA and the other thing ^^ .... made it go away, but then they had to have both the settings "off"

Set water multisampling to low - this is a known issue with Geforce cards introduced in one of the driver updates awhile ago that Nvidia still haven't fixed.