For me, turning the "Effects" to low were the key. I can run everything else, including Filtering, on Medium and 2x AA on.
Before 2.2 I managed to keep Textures at High, but Cagny area in Op Goodwood lagged too much with that, so dropped them to Medium as well. When 2.25 came, Anctoville and the town area in Villers Bocage were still lagging, so started to experiment again.
Disabling Lighting or Shadows isn't really recommended, indoors will look absolutely hideous after that (bright white, for example, or poisonous green; think the original Wolfenstein 3D but without even pre-drawn shadows), lowering the Effects will do the same trick and is hardly noticeable.
Specs: AMD3000+ 32bit single-core, 2GB RAM, GF7600 AGP 256MB, WinXPSP3.