As far as I'm aware the only way to get anti aliasing with HDR is to force it using a tool such as NVinspector. The only problem is that the compatibility modes seem to have massive overheads, especially if you use transparency AA. Even on a relatively well specified PC I'm seeing my GPU max out just looking at certain grass types (Gold coast...) and I've had to resort to low poly grass mods.

Does anyone know of an alternative method of AA (other than FXAA) which might work better with Oblivions janky old bones?