I just finished doing some comparison testing I thought I would share. Nothing earth-shattering here--the results are about what you would expect. I was hoping with 4GB of RAM that Vista 64 would see some performance gains, but that didn't happen. There is essentially no difference in performance of CoH under Vista 32-bit vs 64-bit and DX10 is an equally crappy performer under both. So much so that it seems pointless to even bother running in DX10 mode. Whatever graphics fidelity you hope to gain is more than offset by the fact that you will have to turn down most of the settings in order to maintain a decent framerate.

The Rig
Intel Core 2 Duo 6700
4GB RAM
nVidia 680i chipset
nVidia 8800GTX GPU

The Config
CoH was run with the following settings under both DX9 and DX10 modes:

• Model Quality: High
• Anti-Aliasing: 8X CSAA
• Texture Detail: High
• Shadows: Medium
• Reflections: Low
• Post Processing: On
• Building Detail: High
• Physics: High
• Tree Quality: Medium
• Terrain Detail: High
• Effects Fidelity: Ultra
• Effects Density: Ultra
• Rain Detail: High
• Object Scarring: On
• Model Detail Slider: Max

The Results
.........................DirectX 9
..............Vista 32-bit...Vista 64-bit
Avg FPS...........58.0............57.9
Max FPS...........61.0............62.1
Min FPS............32.0............27.6

..........................DirectX 10
...............Vista 32-bit...Vista 64-bit
Avg FPS...........34.8............32.4
Max FPS...........60.0............60.1
Min FPS.............4.7............. 2.8

Note: The Max FPS is the same for all tests indicating that this is likely CPU limited rather than GPU limited.