Here is a close up allowing you to see the inner baffle that cuts across the motherboard. You'll see that I've cut notches into it that fit over the RAM and other components on the motherboard. Then I use soft foam weatherstripping to seal it gently against the motherboard and the components.

This keeps the air fully separated between the video-card-section and the CPU-section, allowing the cooling fans for each component to work individually and not have to absorb the heat from other sections of the case.

The end result is very satisfactory. I use some software tools to check the case and component temperatures, and everything is operating quite cool even at full tilt playing a high rez 3D game. And it's all whisper-quiet.