ENBSeries

I can't find a reason for this. Any ENB I use, no matter what settings, lags my Skyrim. I take a massive performance hit on my GTX580 and this does not make any sense. It has nothing to do with the ENB settings or my mods. I have disabled all texture packs and additional mods and still receive lag when I enable ENB. Because of this, I simply downloaded an ENB that only used the SSAO feature (so that I may play the game vanilla settings but with the additional AO) AND I STILL HAVE LAG.

Why is this happening, especially on a GTX580?!

Lag or low performance? Have you tried toggle each effect to see which produce issue (the most?)?

SSAO causes the most lag, of course. However, no matter what setting I have the SSAO at, it still lags. This should not be happening with my graphics card when I see people with GTX460's running the ENB settings no problem.

I've done some more digging, and it looks like ENB isn't even the cause of it all. Of course, it adds to the lag, but even with it turn off, I still receive a major performance hit. I've turned off all mods and disabled all additional Nvidia effects. Nvidia AO turned on dips my fps so quickly it's ridiculous. I'm getting 20FPS and, when I go to highly-condensed areas, I get 10fps. This does not make any sense!

What about VRAM, have you checked its usage? If that's not the culprit, try to refresh Skyrim settings by removing (don't delete, just in case) Skyrim.ini, SkyrimPrefs.ini and RendererInfo.txt from My Games/Skyrim and letting the game generate new ones.