I observe annoying hdr graphical bug in Fallout: New Vegas v1.4.0.525, when sli enabled. 2xGeforce GTX 480
Here two examples:

http://www.mediafire.com/myfiles.php#r7hea7ao8pjx4,1

Graphics settings "Ultra" with v-sync enabled, hdr and SLI, antialiasing 4x, AF 10x.
This hdr bug happens near sources of light(lamps, sunbeams) inside buildings, as shown in example "SLI- on HDR -on".
Hdr bug happens near strong sources of light(sunbeams and others) inside buildings.

Reported this to nvidia, here their answer:

"Our lab was able to replicate the problem with your saved game file. Engineer debug the problem and didn't find anything in our driver that would cause the problem so they tested with AMD/ATI DX11 graphics card. As suspected we were able to replicate the same problem using the AMD/ATI card so the problem is likely with the game. We've already forwarded all the data to our developers relation team so they can notify the game developer. This is something they will need to fix on the game side. I'd suggest you contact the game publisher and report the issue and explained to them that NVIDIA has debugged the issue and problem occurs with both NVIDIA and AMD/ATI video cards, and that we believe this is a game issue. Hopefully they can investigate and get this fixed in their next update."

They recommended that I report you about this bug.

I reported this bug on this forum and directly to info@obsidian.net.

You might also send one here: support@gamesas.com. That's the address they give in the stickies.
I realize they published the game but it couldn't hurt to use as many avenues as possible as im sure they
are close with obsidian as well in terms of communication. Just a suggestion.