The Google Nexus 9 Review
by Joshua Ho & Ryan Smith on February 4, 2015 8:00 AM EST- Posted in
- Tablets
- HTC
- Project Denver
- Android
- Mobile
- NVIDIA
- Nexus 9
- Lollipop
- Android 5.0
WiFi Performance
On most tablets, WiFi performance is perhaps one of the most crucial parts of the experience as WiFi is often the primary method of connectivity. Without working WiFi, a tablet is basically useless as the only alternative is either cellular (which is quite rare on most tablets) or Ethernet over USB-OTG, which destroys most of the value of a mobile device.
In the case of the Nexus 9, we see that HTC has fitted this device with a BCM4354 WiFi module to enable two spatial stream 802.11ac. Interestingly, there is some evidence to suggest that HTC has also adopted Cypress Semiconductor’s CapSense controller to enable antenna tuning for the WiFi antennas. However, it’s probable that this solution is only for HTC devices without a Qualcomm Gobi modem as we’ve seen the use of the QFE15xx antenna tuner in previous HTC products. In order to test how the Nexus 9’s WiFi solution performs, we turn to iperf on Android to test throughput across the network, and utilize Asus’ RT-AC68U router to ensure that the device under test will be able to reach maximum performance.
The Nexus 9's WiFi solution performs about as well as one might expect from a BCM4354 solution. For the most part I haven't noticed any reception issues, even when touching/detuning the WiFi antennas.
GNSS
While most of the GNSS solutions that we’ve looked at this year use Qualcomm’s GPSOne/IZat due to the presence of a Qualcomm Gobi Modem, the same isn’t true for the Nexus 9. Instead, Broadcom’s BCM4752 is used here. While this shouldn’t have a massive impact on the speed with which first lock is acquired, in practice Qualcomm’s solution is noticeably faster here as the modem can often provide data to make for a hot fix. At any rate, the Nexus 9 does perform acceptably in this regard. I don’t see any major issues with location performance, although it does seem that the GPS tends to report lower accuracy levels than the Qualcomm solutions that I'm used to. Other than this, the GNSS solution is quite usable.
Misc
While we don't have a proper audio quality test yet, it's clear that the audio codec used is the same Realtek RT5677 codec that we saw in the SHIELD Tablet. Outside of the code, we also see an RT5506 2.55V amp on the 3.5mm jack, along with two NXP TFA9895 amps on the speakers, which are quite good due to their front-facing placement. In practice I don't really see much issue with loudness or quality here, as the speakers can get even louder than the M8 in some situations. We also see a Broadcom BCM2079x NFC chip, which means HCE is fully supported out of the box. Interestingly, the VCM controller is exposed to the OS and is said to be a Texas Instruments DRV201 chip.
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cjs150 - Wednesday, February 4, 2015 - link
No microSD - no chance of me buying it.Tablets are designed to be portable so why do designers never consider the needs of people on the move who may not have access to the cloud (either at all or at prohibitive cost). With 128 mb MicroSD card I can store tons of music, movies, tv shows and watch when I like on holiday
Impulses - Wednesday, February 4, 2015 - link
USB OTG ftwR. Hunt - Thursday, February 5, 2015 - link
Hardly the same thing though.UtilityMax - Sunday, February 8, 2015 - link
They want you to pay royalties to store your stuff in the cloud. I agree that 16GB is somewhat limiting. Half of that space will be used by the OS and applications, with barely anything left for user's data. I'd go with the 32GB model at the very least.NotLupus - Wednesday, February 4, 2015 - link
What's the date today?smayonak - Wednesday, February 4, 2015 - link
Ryan, I noticed that the Nexus 9 offers always-on (screen-off) Google Now activation. I checked in CPUSpy (and other apps) and noticed that even when all cores are parked, this feature works, suggesting that NVidia may have included a custom DSP or third core for audio processing. The +1 core in NVidia's Tegra platform was apparently transparent to the operating system, because it never showed up in CPU activity monitor apps.If it is a custom DSP used for natural language processing, this would probably run afoul of Qualcomm's lock on the IP. Which might explain why NVidia never announced a third core (or DSP) in the Denver platform.
I'm not sure if it's just my imagination at work -- can you confirm or disprove (or speculate) on the existence of a third core? Supposedly Android 5.0 includes support for idle-state audio processing, but only if supported by the hardware. But it would seem hardware support would require some kind of low-energy state processing core. And nothing of the sort appears in NVidia's press releases.
By the way, thank you for the amazingly detailed and insightful review. You guys are amazing.
Andrei Frumusanu - Wednesday, February 4, 2015 - link
Always-on voice activation is done by the audio SoC and has no connection to the main SoC or any DSP. Qualcomm's voice activation is done via the audio chip.smayonak - Wednesday, February 4, 2015 - link
Thanks. I have no doubt that's true, but I can't track down a reference. Anandtech's own article on the subject refers to Motorola's implementation of idle-state audio processing as relying on the X8's low-power cores, dedicated to handling audio processing.Motorola's press release claimed that their X8 included proprietary "natural language" and "contextual" processing cores (which I thought were some kind of analog-to-digital audio-processing DSP, but may be wrong), which allowed for always-on activation of Google Now.
I can count the number of devices that support screen-off Google Now on one hand. The relatively small number of devices with this feature is perplexing. Or maybe no one advertises it?
toyotabedzrock - Wednesday, February 4, 2015 - link
While turning a GPU into a CPU is a great accomplishment then essentially built a CPU that seems designed to benchmark well but will stall endlessly on real world code.Anonymous Blowhard - Wednesday, February 4, 2015 - link
This article is soooo late, clearly you should have just thrown up a half-page blurb with a clickbait title and was shallow enough that it could have just been written hands-off from the tech specs./s
Great read as always. Good things are worth waiting for.