Improving Touch Performance With Windows 8 And Better SNR
Even as Android and Windows 8 grow in popularity, Apple's iPad still enjoys a majority of the tablet market. We've found the iPad to be smoother-feeling and more responsive than even the fastest competitors. And we are correct.
One of the first things Intel did was take stock of the tablet space to see how the most popular sellers performed. This had nothing to do with Jobs' Reality Distortion Field; Apple's iPad was truly faster to respond to touch input than the best Android-based models. Windows 7-based tablet's powered by Pine Trail? The worst of the bunch.
To address this challenge, Intel's engineers approached it like NASA and the Apollo program. They couldn’t change their lot by targeting one specific component or element. Instead, they knew they needed to re-think and re-engineer the whole process, optimizing from the moment your finger hits the screen to the moment your task completes.
The first discovery was that Windows 7’s desktop- and workstation-oriented approach to multi-tasking meant that touch input was given the same priority in the execution stack as everything else. On a fast CPU, waiting for the time slice wasn’t a big deal. On a tablet with a low-power processor, this turned into lag and inconsistent responsiveness. Intel says it worked with Microsoft to create a "fast lane" for user input, so that touch would receive the highest priority. This was implemented in Windows 8, and is featured on all tablets and touch-enabled notebooks (including those running Windows RT). Not surprisingly, Windows 8-based machines seem much more responsive than the slates running Windows 7 we reviewed in the past.
Intel then studied the way gestures were recognized and discovered two interesting points. First, electromagnetic interference from the device's LCD was causing noise in most capacitive touch panels, resulting in a lower signal-to-noise ratio. A poor SNR turned into wasted processing cycles to extract legitimate signal from the noise. Working with OEMs, Intel claims it helped improve the analog signaling involved in touch-capable screens.
Though most mainstream folks believe that claims from audiophiles that cable quality is nothing but a voodoo science, techies know that there are times when cabling makes a measurable difference. It was definitely important to SCSI-based storage subsystems. Then, cables became an issue for 80-conductor IDE cables. Even today, a MacBook Pro can crash with a SATA 6Gb/s SSD unless its cable is also wrapped in aluminum foil for shielding. On a tablet, shielding touch sensors from the noisy LCD panel improved the analog signal-to-noise-ratio to such a degree that latency dropped and accuracy improved, yielding faster and more precise input. Acer is one of the first OEMs implementing Intel's technical contribution, and this is little-known feature of the Iconia W510, W710, and Aspire S7. Not all shipping tablets feature this tuning, but an increasing number of OEMs are joining Intel’s performance optimization program. As an analog technology, this can be applied to any touch-capable device. However, Intel is aggressively approaching OEMs manufacturing x86-based tablets and helping them improve this aspect of their technology.