What were the specs on the machines used for the project?

All of the workstations used NVIDIA Quadro FX 4400s and dual Opterons. The 32-bit workstation was maxed out with 4 GB RAM for each processor and the 64-bit workstation had 8 GB per processor. The render farm was composed of quad-processor Opterons with 32 GB of ram each.

What was the breakdown of the two versions?

The project consisted of two 12-second 24p high definition sequences, one for 32-bit and one for 64-bit. I basically did everything in the scene: Design, modelling, texturing, rigging, animation, lighting, particle effects, and rendering. I also created the music for the clips.

It's important to understand the concept for the comparison. The project was never intended as a direct render speed comparison - for one thing, the 64-bit scene couldn't even be loaded on the 32-bit machine. I'm not sure how valuable it would be to push a reduced detail scene through the 64-bit system just for a raw speed comparison either. I think focusing exclusively on render speed differences would be missing the point of 64-bit advancements: this project was meant to illustrate the bandwidth and scene complexity benefits gained from these 64-bit software and hardware advancements.

It's also important to realise that both renders were done in one render pass all in-camera. No compositing of separate elements. The 64-bit scene included radiosity, area lights, volumetric lights, raytraced shadows, raytraced transparency, raytraced refractions, raytraced reflections, hypervoxel particles, fog, high resolution 4k texture maps, and procedural textures. Also, the raytraced aspects of the scene were compounded by hundreds of creatures all rendered together.

What were the differences between what you could do in the 32-bit environment and the 64-bit environment?

The most profound difference was in the amount of detailed geometry in each scene. With 32-bit Windows, there is a practical limitation to the amount of ram that is accessible to the software. Even though 32-bit hardware supports 4GB of physical RAM, your system is typically limited to about 2 GB of per-process memory. So, all scene resources must be squeezed to fit within that 2 GB limitation. Both scenes had the same environment and background cityscape, but I could only get about 11 one million polygon creatures in the 32-bit scene, while I was able to have 140 creatures in the 64-bit scene. Altogether (background and creatures) it was about 150 million polygons all rendered in one pass! The multiple layers of raytraced refraction and transparency with 140 creatures all rendered together was very exciting for me