For anyone wanting a visual comparison heres a few of the heaviest hit areas in terms of VRam on my Laptop, (the desktop is far better but pointless showing you on the best machine we have) ...
Core2Duo, NVidia 256mb graphics card.
Refer to the debugtext top left in each screen, TextureMem, the T (Total) at the end of that line
http://www.bild.me/bild.php?file=2738345ScreenShot381.jpg
For anyone un-familiar with how Wrye Bash installs those textures, highest number in the install order column wins, so Really Textured Normal maps are over-writing the same ones from Bomrets in my case, and end up in game.
http://www.bild.me/bild.php?file=8339969ScreenShot388.jpg
http://www.bild.me/bild.php?file=3906140ScreenShot383.jpg
http://www.bild.me/bild.php?file=2372246ScreenShot382.jpg
http://www.bild.me/bild.php?file=7704218ScreenShot391.jpg
But I am using HGEC and AMB Roberts body textures so that fella popping in screen in Leyawiin may have had something to do with the slight increase there. Time of day.. more NPCs out of shot :shrug:
Imperial city was close to least in terms of Texturemem, fps goes down to 28 in that area, but never any less than that.
The Great forest was actually the least in terms of Texturemem, though my fps currently goes down to 25-26 in that area. No stutter due to OSR.
So I still have about 100mb VRam to play with, but I like to keep a wedge free just in-case.
Anyone with a 128mb graphics card would be choking with that install list, 256mb however theres bags of room to spare. I considered taking Really out for a true comparison, but cant be bothered

, I think theres enough info above to help determine typical usage with other mods installed.