Skyrim Script Extender (SKSE)
The following mods are bugfixes and patches that are needed to fix the remaining bugs in Skyrim. These range from texture fixes, to scripting and even quest progression. You wouldn't want to play a quest only to find out that it's broken midway.
These are UI enhancement mods for Skyrim which extends the current UI. These move majority of the operations to the keyboard rather than you mousing through the clunky UI. Also throwing in Enhanced Character Edit since Skyrim's character editor is handicapped.
Here's a few character improvement mods that you'd probably want. Most important is the XPMS skeleton and Realistic force because you'd want a more natural physics and movement. Throwing in a few other mods, most especially CBBE because females in the game aren't really female-looking.
While there are a lot of weather, lighting and water mods for Skyrim, I specifically picked Pure Waters and Pure Weather because of the ease of install and almost no FPS drop. It's not as good as ENBs but it's good enough. Alternate start provides you with a shorter start into Skyrim instead of being forced to become the Dragonborn. At the moment, I play a level 19 assassin, with no dragons in sight at all.
Now here's the most important of them all. The following improves Skyrim by reducing oversized textures, removing unneered or unnoticed ones (like the fog) and even improving the rendering of game.
The following are values that have been added/modified from the defaults. Some of them are personal tweaks, which may not work for your machine. These include enabling of threading, completely disabling grass, archery refinements, shadow and controls tweaks, as disabling of postprocessing effects.
Delete both skyrim.ini and skyrimprefs.ini and run the original launcher. It will generate both files with defaults. From the defaults, add/or modify the following. If a section already exists in the file, just add to it. If a key exists, check the value. Most likely I modified them. Skyrim will ignore duplicate sections so be careful.
[General] sIntroSequence= bUseThreadedTempEffects=1 bUseThreadedParticleSystem=1 bMultiThreadMovement=1 bUseThreadedMorpher=1 [Display] iShadowMapResolutionPrimary=256 bAllowScreenshot=0 iPresentInterval=0 [Grass] iMinGrassSize=100 [Combat] fMagnetismStrafeHeadingMult=0.0 fMagnetismLookingMult=0.0 f1PArrowTiltUpAngle=0.0 f3PArrowTiltUpAngle=0.0 f1PBoltTiltUpAngle=0.0 f3PBoltTiltUpAngle=0.0 [Actor] fVisibleNavmeshMoveDist=14000.0000 [BackgroundLoad] bSelectivePurgeUnusedOnFastTravel=1 bBackgroundLoadLipFiles=1 bLoadBackgroundFaceGen=1 bUseMultiThreadedFaceGen=1 bBackgroundCellLoads=1 bLoadHelmetsInBackground=1 bUseMultiThreadedTrees=1 bUseBackgroundFileLoader=1 [Animation] bMultiThreadBoneUpdate=1 [Decals] bDecalMultithreaded=1 [Pathfinding] bBackgroundPathing=1 bBackgroundNavmeshUpdate=1
[General] bUseThreadedParticleSystem=1 bUseThreadedTextures=1 bUseThreadedBlood=1 bUseThreadedMeshes=1 bUseThreadedMorpher=1 bUseThreadedLOD=1 bUseThreadedTempEffects=1 bUseThreadedAI=1 [Imagespace] bDoDepthOfField=0 bDoRadialBlur=0 [Display] iBlurDeferredShadowMask=5 fInteriorShadowDistance=2000.0000 fShadowDistance=1500.0000 iShadowMapResolutionSecondary=128 iShadowMapResolutionPrimary=256 fTreesMidLODSwitchDist=3600.0000 fGamma=0.8400 fSpecularLODStartFade=200.0000 fLightLODStartFade=200.0000 iTexMipMapSkip=0 fMeshLODLevel2FadeDist=3072.0000 fMeshLODLevel1FadeDist=4096.0000 iShadowMapResolution=256 fShadowBiasScale=0.7500 iShadowMaskQuarter=4 iPresentInterval=0 iShadowFilter=1 bDrawShadows=0 bUseSunbeams=0 bSimpleLighting=1 bShadowsOnGrass=1 bTransparencyMultisampling=0 bDeferredShadows=1 [Grass] fGrassStartFadeDistance=0.0000 bGrassPointLighting=0 bDrawShaderGrass=0 [MAIN] fHUDOpacity=1.0000 fSkyCellRefFadeDistance=150000.0000 [GamePlay] fMouseCursorSpeed=1.0000 bShowCompass=1 [Controls] bMouseAcceleration=0 bUseKinect=0 [TerrainManager] fTreeLoadDistance=12500.0000 fBlockMaximumDistance=75000.0000 fBlockLevel1Distance=25000.0000 fBlockLevel0Distance=15000.0000 fSplitDistanceMult=0.4000 [NavMesh] bUseThreadedMeshes=1 [Trees] bUseMultiThreadedTrees=1 bEnableTreeAnimations=0 bShadowMaskZPrePass=1 [Decals] bDecalMultithreaded=1 [LOD] fLODFadeOutMultObjects=8.0000 fLODFadeOutMultItems=1.0000 fLODFadeOutMultActors=15.0000 fLODFadeOutMultSkyCell=1.0000 [BackgroundLoad] bSelectivePurgeUnusedOnFastTravel=1 bBackgroundLoadLipFiles=1 bLoadBackgroundFaceGen=1 bUseMultiThreadedFaceGen=1 bBackgroundCellLoads=1 bLoadHelmetsInBackground=1 bUseMultiThreadedTrees=1 [Water] bUseWaterReflections=0 iWaterReflectHeight=512 iWaterReflectWidth=512 bUseWaterDisplacements=1 bUseWaterRefractions=1 bUseWaterDepth=1
The following images are from Skyrim Performance monitor and taken on my favorite benchmarking spot, the Sundered Towers - a place where you can see a lot of stuff nearby like mountains, plains, hostile NPCs, wolves etc. Since I use the integrated Intel HD graphics, VRAM and GPU measurements are not available for the monitor. But since it's integrated graphics, I assume usage is dumped to RAM.
This was taken enroute to the Sundered Towers from Rorikstead:
This was taken fighting against the tower's NPCs.
From the looks of it, it's what your average mid-to-low-range machine can provide you. The RAM consumption isn't that high, a little under 1GB. The CPU doesn't look like struggling, though the travel benchmark does reach 60%, crunching through the rendering of the terrain. And FPS isn't that bad. It hovers on 30-50 fps on average.
This wouldn't be possible without the help of the Skyrim Beautification Project from which I got most, if not all, bugfixes and mods (I added a few of my own not there). Consider my guide as a trimmed down version of their page, giving your an optimized Skyrim to play.
For the tweaks, I got them from .ini Tweaks - Improving Performance, Gameplay and Visuals as well as SPM's listing of performance-related ini entries. However, I think I didn't apply all of them, like the
iHWThreads and papyrus tweaks as some say it does more harm than good.