Thanks for that, uncleanspirit - there's really no difference I can see between fade touched and ultra as far as her hair is concerned.
I was partially correct: I did some testing and the shadowing on the hair makes a decent difference between HBAO and HBAO Full. Interestingly, despite the game saying changing AO type will only take effect when you reload the game, it actually works immediately, meaning I should be able to switch between them when I want. There's also a massive difference in grass and to a lesser extent other foliage, so I'm definitely going to be using that when I can get away with it. I was lagging really, really badly in The Hinterlands a short while ago, but I restarted the game and performance shot up. That happens every so often; it's like everything gets backed up. I can tell when that's happening, rather than it being an fps issue, because menus and the search radar and sounds start to lag as well. I push the game to the maximum my laptop can handle, so I have to try to balance things out, but now I know I can change AO on the fly that's pretty great. Vegetation doesn't work in the same way - I'll test tomorrow to see if it 'recompiles' if you quick load after changing the setting I get an fps boost in The Hinterlands if I turn vegetation down to medium - which only changes the distance at which it renders, and not the quality of it - which is likely because of all that HBAO (full) that is rendering on the individual blades of grass. Vegetation on its own isn't meant to have that much of an effect on performance, but AO does. As does tesselation - one of the biggest hits along with meshes, AO and MSAA as far as I'm away - but I'm not prepared to sacrifice ultra meshes, and while I compromise and have tesselation at high rather than ultra I don't want to go lower.