On a side note you can enable the game to use 3 + gigs of ram like you can in fallout 3. Steam wont let you like the old one but if you use a fixed exe and fixed launcher with your purchased copy of falloutNV in steam then it will let you alter that fixed exe file with CFF explorer and enable the 4gigs of ram feature. It does help performance big time just like it did in the original.
http://download.cnet.com/CFF-Explorer/3000-2383_4-10564296.html

Which boggles the mind why it isnt 2GB+ fixed by default by the devs. Limiting games to 2GB is ridiculous in this day and age.

Not bad advice, but - still makes use of a crack, which is technically against forum rules.