Month: June 2016

(credit: Aurich Lawson)

The Wi-Fi Alliance industry group is now certifying products that can deliver multi-gigabit speeds and improve coverage in dense networks by delivering data to multiple devices simultaneously.

The new certification program, announced today, focuses on the so-called "Wave 2" features of the 802.11ac specification. 802.11ac is a few years old, but it includes several important features that were not available at launch. One such feature is MU-MIMO (multi-user, multiple-input, and multiple-output), which we wrote a feature on in May 2014. MU-MIMO is powered by multi-user beamforming technology that lets wireless access points send data streams to at least three users simultaneously. Without MU-MIMO, routers stream to just one device at a time but switch between them very fast so that users don't notice a slowdown except when lots of devices are on the network.

With the 80MHz channels supported in 802.11ac Wave 1, each data stream could provide up to 433Mbps and, when coupled with MU-MIMO routers, can send up to 433Mbps to at least three users simultaneously for a total of 1.3Gbps. But in addition to supporting MU-MIMO, Wave 2 also doubles the maximum channel bandwidth from 80MHz to 160MHz, boosting the potential throughput of each stream to 866Mbps. Wave 2 also supports four spatial streams instead of three, further boosting the theoretical maximum capacity. Technically, 802.11ac supports up to eight streams, but the certification program is still at four. Delivering eight streams with these data rates would use a lot of electricity.

Brave? Foolhardy? Desperate? Whatever you might think about AMD's decision to cede the top end of the graphics card market (at least for now) to Nvidia and launch the mainstream-focused RX 480 instead, the fact remains that for £180/$200 it's the best graphics card you can buy. It's faster than Nvidia's GTX 970, and (mostly) faster than an R9 390, making it more than powerful enough to meet the minimum spec for virtual reality—and it'll blitz through demanding 1080p games at a smooth 60FPS too. It even does a decent job at 1440p, so long as you're fine with dialling down a few settings.

As a consumer product, then, the RX 480 is a success, even if one of AMD's core pitches—that it'll help drive VR adoption—is a little suspect. VR headsets still cost well over £500, after all.

But—and sadly, there always seems to be but with AMD—the RX 480 is not a great debut for Polaris 10, its first GPU based on an all-new, theoretically-more-efficient 14nm FinFET manufacturing process. At 150W, the RX 480 sits in the same power envelope as the GTX 1070, yet offers less performance. It runs hotter too, hitting 80 degrees Celsius, even struggling to hit its advertised boost clock at times—and that's in a big, well ventilated case. Compared to AMD's previous cards, it's an improvement, but those were always power-hungry beasts, and the bar has since been raised.

Evernote has been one of the leading note-taking services for some time, with clients for the Web and every major OS. The company recently announced sweeping changes to its "freemium" pricing strategy, which puts a big limit on the "free" tier and raises prices across the board for new and existing users.

The free tier, "Evernote Basic," is now limited to two devices. If you want to access your notes on more than two devices, you'll need to fork over some cash. "Devices" means any device with an official client installed (Evernote apps are available on Windows, macOS, iOS, Android, Chrome OS, BlackBerry OS, and Windows Phone). Using Evernote on the Web does not count as an actual "device," nor do third-party apps that use the Evernote API. Managing device access now works a lot like some music services, where every installed client counts as "a device," and you can log in to a settings page and "revoke access" from each instance.

Evernote's new pricing.

Both paid tiers are getting 40 percent price increases, too. "Evernote Plus," which is now needed by anyone with more than two devices, has seen the price jump from $24.99 per year to $34.99 per year (or $3.99 per month). Evernote Plus limits you to 1GB of uploads per month (the free tier is limited to 60MB). The "Premium" tier moved from $49.99 to $69.99. Premium raises uploaded data per month to 10GB and adds a ton of other features. New users will see the price increase right away, while existing users renewing a subscription will see the new pricing in August.

Space-time gets very messy near the event horizon of a black hole, as this simulated view indicates. (credit: Andrew Hamilton; NSF )

Now that gravitational waves have been detected, theoreticians have been furiously speculating about what we might learn from our gravitational wave observatories. Now that we have a couple of observed black hole collisions under our belt, it is time to consider what we might study. There's some speculation that, depending on the sort of physics at play, the event horizon of a black hole might be studied through gravitational waves.

For this to work, the gravitational wave signal has to change depending on what type of black holes are merging. A recent paper in Physical Review Letters indicates that, unfortunately, reality will probably not cooperate.

No bells on a black hole

When two black holes collide, gravitational waves are emitted as a result of a kind of relaxation process. So far, we have mostly been excited about the waves generated just before the merger, where the objects are spiralling into each other and emitting waves as they plunge through space at very high speed.