|The CPU is not 1X Xbox360.|
The results of specific benchmarks, engines, middleware, could be. But developers have (or will with further optimizations) more processing capabilities than on Xbox360 (and not only thanks to the audio DSP, I/O chip, etc.).
BUT it seems it won't reach a leap comparable to the RAM amount. A moderate advancement, a lot from efficiency (out of order, instructions, cache, etc, i touched upon that before)
For the GPU, it won't be 1,5X Xbox360 when developers will be more accustomed to its specifics, when the SDK, middleware, engines, API, etc, will be further optimized, etc.