My experience with Patch 75 is below but I doubt it will be useful.
Like Patches 73 and 74, the Sheep and the Europe terrains in Patch 75 hard crash my machine very quickly (black screen and then reboot). Offline they crash sometimes a mere second after first rendering the terrain, so I doubt it is a temperature issue. Online, for some bizarre reason, they often last a few minutes or so before crashing.
The ndisles terrain does not (often) crash my machine unless I drive a Jeep through a corn field. That crashes the computer reproducibly. Other fields don't do that, including the tomato plants. Unfortunately I couldn't find any clouds in ndisles and the mission arena (also ndisle terrain) didn't have a B17 mission when I tested, so I can't say what effect clouds have on my fps.
I have to say that (up until the computer crashes) the alpha looks really, really good and my frame rate is good now that I've switched from SSAA to adaptive MSAA.
E8400 @ 3GHz, 4GB RAM, Radeon HD7870 w 2G, WinXP 32bit, DX9.0c, 1920x1080, 4K textures, everything max except Environment 0 and Post Lighting disabled.
PS: are those Windows crash reports that pop up on reboot of any use?