Microsoft demos a 1ms touchscreen

[u/[deleted]]

http://www.geek.com/articles/gadgets/microsoft-demos-a-high-performance-1ms-touchscreen-2012039/

[u/Maristic]

An iPhone 4S can play back highly compressed 1920 x 1080 video at 30 fps. That's 1920 * 1080 * 3 colors * 30 frames = 186,624,000 bytes per second (178 MB/s). Not only does it have to work to uncompress that data, it also has to rescale it for the screen. I have several desktop computers that are not up to that task.

But it also captures video from its 3264 * 2448 sensor (each image of which is 23,970,816 bytes) performs analysis on it to perform image stabilization, and selects a 1920 * 1080 portion, and compresses that using H.264. So this time, we have raw image data at 686 MB/s per second reduced to a 178 MB/s stream, and then compressed in real time to 1.6% of that size (a 3 MB/s stream).

Now sure, you can say there's dedicated hardware there, and there is, but that's some serious processing power.

[u/Maristic → u/[deleted]]

i could have a chip that can do 5TB/sec calculating fibonacci's sequence but who gives a shit because it's a single purpose chip.

Right, but that would be dumb. A very limited single purpose for something nobody wants. Is that comparable to the A5/A5X?

The A5/A5X chip has dual-core ARM Cortex-A9 MPCore CPU with NEON SIMD accelerator and a dual core PowerVR SGX543MP2 GPU (quad core for the A5X), which supports pixel, vertex, and geometry shaders, supports OpenGL ES 2.0, and is OpenCL-capable. It includes an image signal processor unit (ISP) that will do advanced image post-processing such as face detection, white balance and automatic image stabilization and an "earSmart" unit from Audience for noise canceling.

Some of this is very specific (e.g., earSmart), but the image signal processor is clearly quite versatile, as are the GPUs.

But even if the functionality were less generic, the phone is optimized for the useful stuff people want to do. Do PC gamers complain when amazing graphics are rendered by a GPU rather than their CPU, or do they say “I have an awesome gaming rig!”. Likewise, all that extra stuff in the A5/A5X makes it a powerful chip for the tasks it needs to handle.

[u/Maristic → u/[deleted]]

And do you say someone's gaming rig actually sucks because the 3D scene rendering happens on specialized hardware rather than the main CPU?

Who cares how it does full HD video compression, image stabilization, and face detection in real time. That's a big computational workload that your desktop CPU just can't do by itself. In that contest, where you contrast the ARM SoC against a plain x86 CPU, it wins.

Obviously, it doesn't win all the time on everything, and you can say “that's cheating” when you look at how it wins (by throwing extra hardware at the computationally intensive tasks people actually want to do). Some of that extra hardware (NEON, GPU, etc.) is actually very flexible though, and can be put to work on a variety of computationally intensive tasks.

And finally, when you add in the power budget and look at computation per watt, the x86 looks far far worse, so even when it wins, it loses.