Skyrim Performance Boost?

If you've got it working, I suggest making a backup of it before doing any further modding. Also, always start a new game when you mod anything. Using an existing save often causes problems. If you're going to mod, stick with what you've got until you've finished playing through the game once you start.

I still recommend getting a quad core CPU for a gaming rig. Your CPU is not running at 4.4ghz if it's only using 4 cores. It's probably around 2.7 to 3.0 or so at best, that's not bad, but it's not optimal either. Keep two of your cores turned off if you continue to use your 6 core CPU. No existing video game actually uses six cores and the extra cores can sometimes cause issues with some games. I still stand by what I said about six core processors and gaming.

I can recommend some mods for you. I've got all of these plus what you've got installed. I do have a bit more actually, but these are my baseline mods that I always use.

First of all, make sure you either have the archiveinvalidation invalidated mod, or go into your ini and do archive invalidation manually.

Pick up the Skyrim Script Extender as well. A lot of mods need it to run properly.

Secondly, follow the first rule of modding. Always have a clean backup copy of your game without any mods installed. It saves a lot of headaches when things go wrong when modding.

Lastly, load the texture mods you want to have priority last. So if the 4k texture mod is the one you want to have the most influence, add it in last. I usually start with the static mesh improvement mod and then tack on other texture mods on top of it. A lot of the smim is overwritten, but it covers a lot of stuff and textures items the other texture mods miss. So it's best to prioritize the texture mods you want to use and install the ones you want to have the most impact last.

To make it prettier I suggest using:

Better Dynamic Snow
Climates of Tamriel
Trees for Solitude
Whiterun trees
Better Windhelm
Enhanced Blood
deadly spell impacts
enhanced dynamic weather system
better Alchemy and enchantment tables
gildergreen regrown
better embers
Jasus swords
expanded snow systems
Static Mesh Improvement Mod
Apachii Hair
Hectoral Spider Webs
HD Torches 2k-4k Ultra torch
Silly level of detail potions and poisons and wine cellar
Skyrim distance overhaul lod improvement
Better lod waterfalls
Superior Rock textures
Real Ice
Ultimate HD Fire Effects

For better menus and organization:

SkyUI and Headbomb's Better Sorting

You really need:

Uncle Sheogorath's really helpful hints and tips
Uncle Sheogorath does climates of tamriel

I also recommend: Daedric punishment for sweetrolls and Divine punishment for arrows to the knee.

Plus for more variety in enemies and critters:
83Willows_101Bugs
Birds of Skyrim
Improved Fish
Skymomod ['Skyrim monster mod' Google it, it's not on the Nexus or Steamworks but it is well worth hunting down as it adds tons of new enemy types.]
Deadly Dragons
Dragon Lords
Warzones Civil Unrest
Midas Magic

Plus I recommend using Deus Mons as a housing mod. It puts a huge castle on the side of The Throat of the World. It's guarded by a low level dragon that you have to get past to enter the first time. It must be killed as the key is on it's body. It has areas for crafting, enchanting, alchemy, and smithing. Plus there is lots of storage and several NPCs.

If you're using a housing mod, I suggest adding the 'Spouse to custom home mod' as well.

Also you could use the Leveler's Tower, which is a huge cheat. It has item generators, a room that generates mobs, a soul gem dispenser, one item with every enchantment in the game to disenchant to unlock all the enchantments for the enchanting table, plus a cheat room with switches for raising all of your character stats, a teleport room, as well as a few sets of very powerful weapons and armor. It does not conflict with Deus Mons so you can have both if you'd like. The tower is located just down the road from the exit to the Helgen dungeon/cave.

I actually recommend the Leveler's Tower even if you don't use it to cheat, as it's a great tool for testing mods out. The armor provides enough protection to check out modded areas, the teleport function allows for quick travel to distant areas, and the leveling cheats allow quick access to late game items and enemies.

I've not played Skyrim the same way twice, but the above [plus the ones you've already mentioned] are mods I use pretty much every time I play through it again.