Thought that was completely unacceptable.
So I've been doing anything and everything to make my PC scream with ini and hardware tweaks. So far, the only thing to really slash my FPS was forcing Ambient Occlusion on High Quality. Brought me down to 30-35FPS. Surprisingly, not even significantly increasing the distance in which objects/trees/etc. fade was enough to put a serious damper on my rig. Lowest I'll see it go is 27FPS and generally 30-35FPS, which is totally legit for this type of game.
It wasn't until I set my iShadowMapResolution to 8192 that I had unplayable frame rates, but 4096 is totally acceptable.
SkyrimPrefs.ini
fBrightLightColorB=1.0000
fBrightLightColorG=1.0000
fBrightLightColorR=1.0000
iStoryManagerLoggingEvent=-1
bEnableStoryManagerLogging=0
[Imagespace]
bDoDepthOfField=1
iRadialBlurLevel=2
[Display]
iBlurDeferredShadowMask=3
fInteriorShadowDistance=3000.0000
fShadowDistance=8000.0000
iShadowMapResolutionSecondary=4096
iShadowMapResolutionPrimary=8192
iShadowSplitCount=2
iMaxAnisotropy=16
fLeafAnimDampenDistEnd=4600.0000
fLeafAnimDampenDistStart=3600.0000
fTreesMidLODSwitchDist=10000000.0000
fGamma=1.0000
fDecalLOD2=1500.0000
fDecalLOD1=1000.0000
fSpecularLODStartFade=2000.0000
fShadowLODStartFade=200.0000
fLightLODStartFade=3500.0000
iTexMipMapMinimum=0
iTexMipMapSkip=0
iWaterMultiSamples=4
iMultiSample=8
iShadowMode=3
bTreesReceiveShadows=1
bDrawLandShadows=1
bFull Screen=1
iSize H=1200
iSize W=1920
fMeshLODFadePercentDefault=1.2000
fMeshLODFadeBoundDefault=256.0000
fMeshLODLevel2FadeTreeDistance=2048.0000
fMeshLODLevel1FadeTreeDistance=2844.0000
fMeshLODLevel2FadeDist=10000000.0000
fMeshLODLevel1FadeDist=10000000.0000
iScreenShotIndex=167
bShadowMaskZPrepass=0
bMainZPrepass=0
iMaxSkinDecalsPerFrame=25
iMaxDecalsPerFrame=100
bFloatPointRenderTarget=0
sD3DDevice="NVIDIA GeForce GTX 570"
bFXAAEnabled=0
iShadowMapResolution=4096
fShadowBiasScale=0.1500
iShadowMaskQuarter=4
iAdapter=0
iPresentInterval=1
iShadowFilter=3
bTransparencyMultisampling=1
bDrawShadows=1
[Grass]
b30GrassVS=1
fGrassStartFadeDistance=7000.0000
fGrassMaxStartFadeDistance=7000.0000
fGrassMinStartFadeDistance=0.0000
[MAIN]
bGamepadEnable=1
bCrosshairEnabled=0
fHUDOpacity=1.0000
bSaveOnPause=1
bSaveOnTravel=1
bSaveOnWait=1
bSaveOnRest=1
fSkyCellRefFadeDistance=150000.0000
[GamePlay]
bShowFloatingQuestMarkers=1
bShowQuestMarkers=1
iDifficulty=4
[Interface]
bDialogueSubtitles=0
bGeneralSubtitles=0
bShowCompass=1
[Controls]
fGamepadHeadingSensitivity=1.0000
fMouseHeadingSensitivity=0.0125
bAlwaysRunByDefault=1
bInvertYValues=0
bGamePadRumble=1
bMouseAcceleration=1
[Particles]
iMaxDesired=750
[SaveGame]
fAutosaveEveryXMins=15.0000
[AudioMenu]
fAudioMasterVolume=1.0000
fVal7=1.0000
uID7=0
fVal6=1.0000
uID6=0
fVal5=1.0000
uID5=0
fVal4=1.0000
uID4=0
fVal3=1.0000
uID3=94881
fVal2=0.4000
uID2=466532
fVal1=1.0000
uID1=554685
fVal0=0.8000
uID0=1007612
[Clouds]
fCloudLevel2Distance=262144.0000
fCloudLevel1Distance=32768.0000
fCloudLevel0Distance=16384.0000
fCloudNearFadeDistance=9000.0000
[TerrainManager]
fTreeLoadDistance=75000.0000
fBlockMaximumDistance=250000.0000
fBlockLevel1Distance=70000.0000
fBlockLevel0Distance=35000.0000
fSplitDistanceMult=1.5000
bShowLODInEditor=0
[NavMesh]
fObstacleAlpha=0.5000
fCoverSideHighAlpha=0.8000
fCoverSideLowAlpha=0.6500
fEdgeFullAlpha=1.0000
fEdgeHighAlpha=0.7500
fEdgeLowAlpha=0.5000
fTriangleFullAlpha=0.7000
fTriangleHighAlpha=0.3500
fTriangleLowAlpha=0.2000
fLedgeBoxHalfHeight=25.0000
fEdgeDistFromVert=10.0000
fEdgeThickness=10.0000
fPointSize=2.5000
[Trees]
bRenderSkinnedTrees=1
uiMaxSkinnedTreesToRender=4000
[Decals]
uMaxDecals=1000
bDecals=1
bSkinnedDecals=1
uMaxSkinDecals=100
uMaxSkinDecalsPerActor=60
[LOD]
fLODFadeOutMultObjects=30.0000
fLODFadeOutMultItems=30.0000
fLODFadeOutMultActors=30.0000
fLODFadeOutMultSkyCell=5.0000
[Launcher]
bEnableFileSelection=1
bShowAllResolutions=1
uLastAspectRatio=4
[BlurShaderHDR]
bDoHighDynamicRange=1
[BlurShader]
bUseBlurShader=0
[Water]
iWaterReflectHeight=1024
iWaterReflectWidth=1024
bUseWaterDisplacements=1
bUseWaterRefractions=1
bUseWaterReflections=1
bUseWaterDepth=1
fBrightLightColorB=1.0000
fBrightLightColorG=1.0000
fBrightLightColorR=1.0000
iStoryManagerLoggingEvent=-1
bEnableStoryManagerLogging=0
[Imagespace]
bDoDepthOfField=1
iRadialBlurLevel=2
[Display]
iBlurDeferredShadowMask=3
fInteriorShadowDistance=3000.0000
fShadowDistance=8000.0000
iShadowMapResolutionSecondary=4096
iShadowMapResolutionPrimary=8192
iShadowSplitCount=2
iMaxAnisotropy=16
fLeafAnimDampenDistEnd=4600.0000
fLeafAnimDampenDistStart=3600.0000
fTreesMidLODSwitchDist=10000000.0000
fGamma=1.0000
fDecalLOD2=1500.0000
fDecalLOD1=1000.0000
fSpecularLODStartFade=2000.0000
fShadowLODStartFade=200.0000
fLightLODStartFade=3500.0000
iTexMipMapMinimum=0
iTexMipMapSkip=0
iWaterMultiSamples=4
iMultiSample=8
iShadowMode=3
bTreesReceiveShadows=1
bDrawLandShadows=1
bFull Screen=1
iSize H=1200
iSize W=1920
fMeshLODFadePercentDefault=1.2000
fMeshLODFadeBoundDefault=256.0000
fMeshLODLevel2FadeTreeDistance=2048.0000
fMeshLODLevel1FadeTreeDistance=2844.0000
fMeshLODLevel2FadeDist=10000000.0000
fMeshLODLevel1FadeDist=10000000.0000
iScreenShotIndex=167
bShadowMaskZPrepass=0
bMainZPrepass=0
iMaxSkinDecalsPerFrame=25
iMaxDecalsPerFrame=100
bFloatPointRenderTarget=0
sD3DDevice="NVIDIA GeForce GTX 570"
bFXAAEnabled=0
iShadowMapResolution=4096
fShadowBiasScale=0.1500
iShadowMaskQuarter=4
iAdapter=0
iPresentInterval=1
iShadowFilter=3
bTransparencyMultisampling=1
bDrawShadows=1
[Grass]
b30GrassVS=1
fGrassStartFadeDistance=7000.0000
fGrassMaxStartFadeDistance=7000.0000
fGrassMinStartFadeDistance=0.0000
[MAIN]
bGamepadEnable=1
bCrosshairEnabled=0
fHUDOpacity=1.0000
bSaveOnPause=1
bSaveOnTravel=1
bSaveOnWait=1
bSaveOnRest=1
fSkyCellRefFadeDistance=150000.0000
[GamePlay]
bShowFloatingQuestMarkers=1
bShowQuestMarkers=1
iDifficulty=4
[Interface]
bDialogueSubtitles=0
bGeneralSubtitles=0
bShowCompass=1
[Controls]
fGamepadHeadingSensitivity=1.0000
fMouseHeadingSensitivity=0.0125
bAlwaysRunByDefault=1
bInvertYValues=0
bGamePadRumble=1
bMouseAcceleration=1
[Particles]
iMaxDesired=750
[SaveGame]
fAutosaveEveryXMins=15.0000
[AudioMenu]
fAudioMasterVolume=1.0000
fVal7=1.0000
uID7=0
fVal6=1.0000
uID6=0
fVal5=1.0000
uID5=0
fVal4=1.0000
uID4=0
fVal3=1.0000
uID3=94881
fVal2=0.4000
uID2=466532
fVal1=1.0000
uID1=554685
fVal0=0.8000
uID0=1007612
[Clouds]
fCloudLevel2Distance=262144.0000
fCloudLevel1Distance=32768.0000
fCloudLevel0Distance=16384.0000
fCloudNearFadeDistance=9000.0000
[TerrainManager]
fTreeLoadDistance=75000.0000
Those are my ini's with nVidia Inspector forcing AO, 8xQ AA, 8xSS TrAA (Supersampling Transparency Anti-aliasing) and 16x AF.
Some screenshots:
http://maxxron.imgur.com/all/