In our Nexus 7 review video, we briefly talked about the performance differences between the new Nexus 7 tablet, last year's Nexus 7, and the LG-made Nexus 4 smartphone. Here, I'm going to dive into that testing in greater detail and discuss the day-to-day experiential differences between those devices.
First, let's recap why performance was potentially a concern when evaluating this year's Nexus 7 (at least on paper), in light of the performance of last year's model. The 2012 Nexus 7 ran on Tegra 3, which was an Nvidia-designed CPU and GPU combination system-on-a-chip. On the CPU side, the Tegra 3 T30L was based on ARM's Cortex A-9 spec, with four A9 cores clocked to 1.2GHz and a special low-power companion clocked to 500MHz. Graphics were provided by 12 ULP GeForce cores clocked to 416MHz, and the die was manufactured on a 40nm process. And while the tablet was (and still is) very usable, users suffered from bogged down performance over time, and the Tegra 3 is dated by today's standards.
Looking at the specs of this year's Nexus 7, then, was a little worrying because of the combination of two factors: the new high-resolution screen and the use of a Snapdragon S4 Pro APQ8064 processor. A 1920x1200 resolution screen is going to be more demanding on the SoC (at least the GPU) for games and web rendering, and the Snapdragon S4 Pro looked to be the same chip as the one used in the Nexus 4--which has a 1280x768 resolution panel. Day-to-day performance on the Nexus 4 isn't sluggish after six months, but I was curious how that chip's performance would translate to a larger device.
It turns out those spec concerns weren't warranted, because it's been discovered that the Snapdragon S4 Pro inside the 2013 Nexus 7 isn't the same chip as the one inside the Nexus 4. Even though they're both labelled by Qualcomm as Snapdragon S4 Pro APQ8064 processors, the Nexus 7's SoC employs four of Qualcomm's high-end Krait 300 cores, which were only announced at the beginning of this year. The S4 Pro in the Nexus 4 uses Krait 200 series cores, though both are clocked at 1.5GHz. Krait 300, as Anandtech's Brian Klug explains, is used in Qualcomm's Snapdragon 600 SoCs, like the one found in the HTC One. But those Snapdragon 600 chips are clocked at 1.7GHz, which explains the S4 Pro moniker for the chip in the new Nexus 7. Confusing, right?
The bottom line for specs: the 2012 Nexus 7, 2013 Nexus 7, and Nexus 4 all use different processors, with the Nexus 7's chip being most akin to clocked down version of the chip in the HTC One. The expectation is that the new Nexus 7's SoC is capable enough to drive app and game performance on its high-resolution screen, and that its performance should be more comparable to the excellent HTC One than the (still great) Nexus 4. Time to do the numbers.
Synthetic benchmarks are more useful for making direct comparisons between hardware architectures than for holistic performance evaluation. If you're interested in testing your own devices, use this guide from our own Ryan Whitwam. I tested the new Nexus 7, last year's Nexus 7, the Nexus 4, and the HTC One using Ryan's recommended free AnTutu tool, which evaluates CPU, GPU, and RAM independently. Here are the results.
|Score||Nexus 7 (2013)||HTC One||Nexus 4||Nexus 7 (2012)|
The results aren't all that surprising, given what we know about the internal hardware. Even though they're both clocked at 1.5GHz, the new Nexus 7's Krait 300 architecture gives it a significant advantage over the Nexus 4 on the CPU side, and even a leg up on the GPU side (even though they're both using Adreno 320 graphics). The bigger surprise was how much better the HTC One performed over the Nexus 7, especially in RAM, since it's only using 2GB of LPDDR2--just like the Nexus 4. The 2GB of 1600MHz DDR3 low voltage RAM in the new Nexus 7 is theoretically one of the ways it surpasses the performance of the Nexus 4. Last year's Nexus 7 came in last, as expected.
One the graphics side, I wanted to choose a benchmark that would run rendered graphics on native resolution. Some games will run at a fixed resolution (for example 720p) and scale up, which is less taxing on a smartphone and tablet's GPU, and by association battery life and temperature. 3D games that run at native resolution may struggle on a 1920x1080 screen, let alone a 1920x1200 screen. That's the resolution of 24" monitors. 3DMark for Android has an "extreme" test that runs at native res, rendering graphics in OpenGL ES2.0. Unfortunately, last year's Nexus 7 couldn't handle the workload, and 3DMark repeatedly crashed on our unit, despite several reinstalls. Here are the numbers for the other three current devices.
|Score||Nexus 7 (2013)||HTC One||Nexus 4|
|Graphics test 1||32fps||33fps||20fps|
|Graphics test 2||23fps||23fps||14fps|
The Nexus 7 and HTC One performed very similarly in these tests, and the difference in their CPU clock speeds didn't account for any noticeable difference in framerate. The Nexus 4, however, struggled a bit more, despite only rendering at 1280x768. This test boded very well for the new Nexus 7, showing that graphics performance wasn't compromised for the low price and that it could keep up with the best Android smartphones.
So what about day-to-day experience? Anecdotally, the new Nexus 7 feels exactly as fast as the numbers indicate: snappier in launching apps and smoother in scrolling through webpages than the Nexus 4, but not quite as responsive as the HTC One. But these are differences you'd only notice if you owned and use all three devices. As you could see in our video, there were a few times where the Nexus 7 hitched when initially scrolling down a webpage with embedded videos. Once a page fully loads, that hitch all but disappears, and was never once noticeable on the home screen. If anything, the fast app launching and loading performance on the Nexus 7 brought to attention how dated last year's Nexus 7 now feels. That Tegra 3 tablet was good enough at the time, and is still technically good enough now, but the new Nexus 7 blows it away in almost every experiential way.
As we say in the video review, this really feels like a no-compromises tablet. It's $30 more than what the first-gen Nexus 7 launched at last year, but all our testing indicates that this premium is well worth it, even if you already bought last year's model.