How much vram for skyirm mods at 1280x1024.

depends on the mods. if your still downloading 1k-2k textures, your screen size wont care since the game engine is still loading those file sizes. but you can resize your textures if youd like. your not going to notice a difference between 1k and 512 textures at that resolution.

also if your using an enb... you cannot use 4xmsaa since the two dont mix. you can download an smaa injector, which is just as good as msaa, but much more performance friendly.

but ideally you should be using the enboost features of the enb, skse to raise the 256mb box limit to 512mb, and cleanmem scheduler to flush randoms.