Ok, here are my Black Death results. I always run through the track twice with each set of changes, because the first run always stutters, the second run smooths out.
1) Frames 4538, Time (ms) 217138, Min 3, Max 60, Avg 20.899
DepthBits =24
StencilBits=8
2) Frames 4596, Time (ms) 217452, Min 4, Max 59, Avg 21.136
DepthBits =24
StencilBits=8
3) Frames 4545, Time (ms), 217788, Min 3, Max 61, Avg 20.869
DepthBits =32
StencilBits=16
(only changed in documents)
4) Frames 4612, Time (ms) 217957, Min 4, Max 58, Avg 21.160
DepthBits =32
StencilBits=16
(only changed in documents)
5) Frames 4534, Time (ms) 216676, Min 3, Max 60, Avg 20.925
DepthBits =32
StencilBits=16
(Changed in docs and game file)
6) Frames 4594, Time (ms) 217235, Min3, Max 58, Avg 21.148
DepthBits =32
StencilBits=16
(Changed in docs and game file)
All settings on Medium plus grass, shadows, roads - AA off, epi off, ssao off, vsync off. All CCC settings at 'application controlled' and highest performance settings.
Sorry pupo, no difference here. I wonder what else could be causing it for you? Strange.
Edit: this test was done with my 5770 before I swapped it for the gtx570 in the sig.