The jump in graphical fidelity comes about as Doom 4 is targeted to run at 30 frames per second, whereas Rage will run at 60 frames per second. Carmack claims this allows id to throw "three times as much horsepower" at Doom 4. nope
"[Doom 4 is] going to be a 30Hz game," he told Maximum PC. "It's going to look like a totally new game engine on there, even though it's going to be built on the four years of effort that we spent developing this generation of technology."
No platform or release details have been revealed for Doom 4, which was unveiled in a surprise announcement earlier this year. However, the id Tech 5-powered Rage will arrive on PC, PS3, Xbox 360 and Mac, suggesting similar platforms for Doom 4.
On the subject of id Tech 5, Carmack noted that the PC, PS3 and Xbox 360 editions of the hardware can all use the exact same build with no issues, whereas the Mac engine requires an extra conversion step.
"We wanted to say OK, here's the build and run the same build on the PC, the 360, and the PS3," he explained. "We still have to go through one extra step to build it on the Mac. But it really does work that way on the other [console] platforms."
More details on Rage, Doom 4 and id Tech 5 are expected at Quakecon, which kicks off at the end of July. In the meantime, scope out our recent interview with John Carmack and the below Rage trailer for more information.