[mpakes]

The smoothness is a huge improvement, but touch-latency and scrolling physics are still huge problem areas, even in Jelly Bean on Nexus 7 hardware.

In testing, I've enjoyed the Nexus 7 form-factor, but the iPad's responsiveness and scroll behavior are such a relief when I switch back. It was immediately noticeable, even when beta-testing an app on my old iPad 1 today.

[ChuckMcM]

And what it shows is investment.

There should be rock solid high performance graphics drivers for every Android phone. There aren't. The chip manufacturers aren't helping because they won't let 'regular' people get access to real documentation, Google isn't helping because it won't put 4 or 5 engineers on it full time. ODMs don't do it because if Google doesn't do it why should they, they take the crappy vendor supplied driver and run with it.

So far there is no penalty to a chip vendor for having crappy video drivers. This is an area where nVidia invested in strongly to win the PC hardware space but has not done squat in for the Android space, at least it isn't visible outside nVidia.

The Nexus 7 is the first Android tablet to even kinda sorta look like the way the iPad moves. This is something that totally confounds me about Google's internal process.

[tmurray]

Speaking as an ex-GPU driver guy, you're off by an order of magnitude about the number of engineers it takes to make a solid graphics driver. For a good GPU driver that makes smart choices about display, power management, OGLES, etc, you're looking at 30-40 people, not 4 to 5. Multiply that by every chipset for Android available (NVIDIA Tegra, ARM Mali, Qualcomm Snapdragon, Imagination PowerVR, Samsung Exynos assuming they build their own GPU eventually), and it's prohibitive to do that all within one company. It's also harder for Android than iOS because of the architectural diversity within the Android GPU market. Optimizing for a TBDR like PowerVR is different than optimizing for a standard renderer with a Z-buffer. iOS can make a bunch of assumptions that Android can't due to dependence on a single vendor.

[rys]

That's not true. The graphics hardware vendors do help (we have a well-staffed team of dedicated Android driver engineers, much more than your 4 or 5) and we work directly with Google's myriad Android graphics engineers. The drivers are as stable and fast as we can all make them, given Android's architecture and the timescales involved with Android releases and customer hardware releases.

[zurn]

iOS devices use the same PowerVR GPU family as many (most?) Android devices. Is there evidence suggesting they did their own driver? I guess one could tell by comparing what kind of GLES bugs exist in iOS vs Android.

edit: seems Apple's docs refer to Imagination's web site for GPU programming details, which would suggest they're using imgtec's driver. (http://developer.apple.com/library/ios/#documentation/3DDraw...)

[tmurray]

I wonder how much of this is hardware versus software. Keep in mind that end-to-end latency has a number of possible sources:

- touch digitizer - CPU to do something with the input - GPU to start rendering the result - display to show the change

In particular, I worry about the first and the last. Apple can get away with using extremely high cost parts in the iPad due to vertical integration (look at the physical size of A5X, for example), whereas Android vendors generally can't. Considering that CPU and GPU are generally selling points whereas touch digitizer performance and display response time are not, it would be tempting for a margin-sensitive OEM to cut corners on those two things.

There is plenty of precedent for this: look at the grey-to-grey response time of the original Xoom.

[bsphil]

I always assumed that it was the level of abstraction required for Android to be able to function on a wide variety of hardware. iOS on the other hand is running on a relatively tiny number of devices with hardware chosen for use by themselves.

Even with a difference in milliseconds you'd still be able to discern between "smooth" and "not smooth".

[heretohelp]

These sorts of problems are why, after owning two Android phones I switched to an iPhone 4. I don't even care for apple that much (Linux user).

"Relief" is a good word for what I felt.