What optimizer textures program does is compress the textures so they are much smaller and in theory it should help with performance/crashes.
On top of that, if you want to improve stability of the game and visual quality, use
Phinix Natural ENB, which is the one I use - you can use any other ENB that includes the latest ENB version, which comes with the features of
ENBoost. And also install
Safety Load and
SSME (or the latest SKSE alpha which includes the features of SSME).
And yes, SFO can hurt framerate depending on your rig, although I barely notice any drops in my game.
I explained the process of modding Skyrim as well as I could in
this post, although the "mods I use" section is a bit outdated.