有關HALO不能開FSAA,請參閱
Technical and Performance FAQ

1.3.1 Is hardware anti-aliasing supported?
No. Halo renders everything to multiple off-screen surfaces instead of directly to the D3D back buffer and hardware anti-aliasing is applied on the back buffer only. For Halo, we have to do this because some of the effects (such as the active camouflage or the zoom scope) require the back buffer as source data.

一堆鳥話,反正HALO就是不能與FSAA相容就是了.