This fixes the NPC lag and the frameskipping issue, but remember it is work in progress and it's just ... inconvenient for some
But if it was, you wouldn't be here reading this anyway. Try it out.
http://forums.guru3d.com/showthread.php?p=3742890 General, read the top post.
http://www.newvegasnexus.com/downloads/file.php?id=34832 For New Vegas
http://www.fallout3nexus.com/downloads/file.php?id=8886 - For Fallout 3 1.7
This worked perfectly in Fallout 3, it helps in Fallout new vegas I'm still sorting out some settings, but there is a great improvement. It went from unplayable to now barely playable.