Results may vary. Backed up unused saves except for last one to a different location. Deleted the Fallout.ini, FalloutPrefs.ini, and RendererInfo.txt in MyGames\FalloutNV folder. After backing up, edited the Fallout_default.ini in Steam\steamapps\common\fallout new vegas\ folder as follows:

bActorLookWithHavok=1
bUseThreadedBlood=1
bUseThreadedMorpher=1
bDisableHeadTracking=1
iPreloadSizeLimit=78643200
bUseHardDriveCache=1
bUseThreadedTempEffects=1
bUseThreadedParticleSystem=1
bUseThreadedAI=1

[Display]
bHighQuality20Lighting=1
bAllow30Shaders=1

[HAVOK]
iNumHavokThreads=5

[BackgroundLoad]
bUseBackgroundFileLoader=1
bBackgroundLoadLipFiles=1
bLoadBackgroundFaceGen=1

[Grass]
iMinGrassSize=110

Loaded the game and allowed it to set default settings (Ultra in my case), changed the resolution to 1920x1200 set the AA to 4 and AF to 15 and then started it up. Been getting good smooth gameplay usually between 45 and 60 fps. I usually do ~ toggleemotions as well. CCC 3D settings are Advanced Catalyst A.I., High Quality Mipmap, Wait for vertical refresh: On, unless application specifies, Super-sample AA, and Triple Buffering checked. Reducing the Mipmap Detail and the AA Mode can improve frame rates at expense of some quality. Using the 10.10 drivers and the 10.10c hotfix.

Specs:
E8600, HD5870, 4G DDR2 800MHz Ram, running steam and game off a SSD.