Originally Posted by Relic
The hardware can easily handle it, the Adreno 320 is faster then Power SGX 543 found in the iPhone 5. The lag is probably in Android itself, Qualcomm chip users found that by modifying the GPU conf to reflect this,"ondemand, down_differential 30, up_threshhold 70" greatly increases the speed of the games and overall smoothness of the GUI. That being said, which videos have you seen, the ones I've seen so far showed no such lag.
Hmm, I'm not sure I'd be so quick in saying that the hardware can handle it as easily, and at least I am of the opinion of having "seen" otherwise.
Note, that even the rMBP has trouble pushing as many pixels around at this resolution and those have much more powerful chips, especially the dedicated ones.
Certainly you're right in saying that Android in itself might be responsible for a good part of that and that's certainly true. It becomes obvious when seeing that games run so much better than anything running on top of Dalvik, but then again, this is long known and a problem based on poor technological choice noone can reverse now. I am convinced apps won't be a pleasure on this device.
Have a look at the Google presentation video, you'll notice many instances during the presentation where they were trying very hard to scroll as little and as slowly as possible and especially trying to avoid any kind of momentum scrolling, since this would obviously slow things down even more because of the repeated delta calculations resulting in more dropped frames.
Also take a look at early hands on videos, such as at the Verge, where you can see how low the frame rate drops when trying to rotate Google Maps in 3D mode. And note this is running on top of OpenGL. This is especially curious, since Google Maps seems to run much better on top of iOS, than on even highend Android devices. I blame this not only on the underlying system, but also at the combination with constantly increasing resolutions and the push towards 1080p even in Android phones these days.