Carmak said a console can run a game 2x faster than equal PC hardware. On Twitter. This isn't a scientific axiom. You can't turn that into a reversible math formula and make the comparison using 2x "faster" hardware because establishing what "2x faster" is is not that simple.
This isn't DBZ where there's a single "power" measurement. A GPU is not a linear engine. It has a lot of hardware that performs several tasks, each one with it's own upper limits. How many texels it can read, how many vertex/pixel shader instructions it can run, how long each different shader instruction takes to run, how many polygons can it assemble, the latency for fetching uncached texture data, how big the texture cache is, how many pixels it can write to the framebuffer, what's the blending performance, how fast can it perform depth/stencil tests... all of that has an impact on how a game will run, and that's not even getting into the API/driver side of things (command queuing strategy, what's the penalty for switching render states, etc).
When Carmak said a console can run a game 2x faster than equal hardware, he wasn't talking about magically doing the same thing, but faster. No amount of "coding to the metal" will increase fillrate or make the GPU run shaders faster. It's about doing things differently (or not doing things at all) and finding out a way for it to still look good. In a console the ceiling(s) are always in the same place, so it's possible to figure out what the bottlenecks are and what you should do to avoid them. It's about smoke and mirrors.
When Carmak said a console can run a game 2x faster than equal hardware, he was talking about equal hardware, which the GeForce 8800GT definitely isn't. The GF8 was a major breakthrough in GPU architecture, specially when it came to shader performance. It was also a DirectX 10 GPU, which brought forth several advancements to reduce the DX9 draw call costs, like constant and state buffers. Its performance is in an entirely different league than the PS3 and 360.
Finally, when Carmak said a console can run a game 2x faster than equal hardware, he was talking about the PS3 and the 360. He was not postulating an axiom that applies to all hardware ever. Current gen hardware actually lost some of last gen's advantages: they have drivers, need to virtualize GPU resources and are stuck with subpar general purpose x86 CPUs instead of SIMD number crunchers.
evil may cry at 30fps (without fraps) at a higher resolution than either of the console versions.
