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I have not tried to optimize snow performance. I would look for Cyanaras posts here or on steam. He may have something.
One major FPS killer you can control is SNOW DETAIL.
The terrain mesh (triangle group) that makes up the terrain is about 28 times more triangles per meter than normal maps. That is a huge amount. When you turn the snow detail down the game stops using this dense triangle mesh to show footprints. It still places small textures on the map where foot prints are. But it does not deform the terrain mesh.
As a side note, I have a feeling that many bug splats come from terrain deformation code. As a summer game goes on the terrain gets adjusted by bombs, mortars, etc. So you can play a few games before you run the risk of a bug splat. Winter maps also deform the terrain for foot prints and vehicle paths and the terrain meshes are much larger. So you should always restart after a single snow map game. And of course playing larger team games will increase your chance of long terrain changing games and the possibility of crashing. The game also has to place textures on the terrain to show bomb damage etc. This creates new meshes on the fly also.
Some people say they have older PCs and never crash, so maybe how the triangle meshes are dealt with on newer cards is the issue? I am not smart enough for that question.
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