Xbox One GPU is impressive, although the PS4 is more impressive due to the DDR5 memory.
I was curious on this topic - where does the new XBox One / PS4 GPU land vs a PC GPU.
This gives a general idea.
Obviously the dedicated video card, not sharing system RAM, would be faster in absolute terms. The APU if it were operating at peak for more than a fraction of a second, would have the CPUs starved for memory.
However, the absolute capability of the XBox One APU vs a GTX 560 Ti is not far off.
Edit : Note the memory and pixel fill rates of the PS4 are about double that of the XBox One, making it very close to a 560Ti.
GTX 560 Ti
Memory Bandwidth: 128.256 GB/sec
FLOPS: 1262.592 GFLOPS
Pixel Fill Rate: 26304 MPixels/sec
Texture Fill Rate: 52608 MTexels/sec
Xenos Xbox 360 GPU: 240 Gflops
Xbox One GPU: 1310 Gflops
Xenos Pixel fillrate: 4,000Mpix/s
Xbone Pixel fillrate: 13,648Mpix/s
Xenos Texel fillrate: 8,000Mtex/s
Xbone Texel fillrate: 40,944Mtex/s