Google Nexus 9: Preliminary Findingsby Joshua Ho on November 3, 2014 1:00 PM EST
While there’s a great deal of ground to cover on the tablet as a whole, one of the most interesting aspects of the Nexus 9 is the SoC. While we’ve tested Tegra K1 before, we were looking at the more traditional Cortex A15 variant. The Denver variant (Tegra13x) is mostly similar to Tegra K1-32 (Tegra12x), but instead the CPU cores are a radically different design. In order to get an idea for how this translates into real world we can look at a few of our standard benchmarks in this area, although Google Octane couldn’t complete a full run. This build of Android clearly has AArch64 active, which means that we should be able to directly compare the Nexus 9 to the iPad Air 2 for performance.
As one can see, at least at this stage in development the Nexus 9 can show some level of promise at times, but can be a bit disappointing in others. In SunSpider, Denver is generally even slower than Krait. However, in a benchmark like Kraken the Nexus 9 easily pulls ahead to take the top spot. In Basemark OS II the Nexus 9 does well overall but this seems to be due to its graphics performance/GPU performance and storage performance rather than CPU-bound tests like the system and web tests. It seems that when the code morphing systems works as expected, Denver can deliver significant amounts of performance. However, when such code morphing falls flat its true performance with a dual core, 2.3 GHz configuration is around that of a four Krait core CPU system at similar clock speeds. Once again, it's important to emphasize that this build is far from complete so performance should improve across the board with launch software. The fact that Tegra13x can approach A8X in CPU performance in some tests is definitely interesting to see.
While Denver's performance is a bit mixed, it's worth taking a look at battery life to see how Denver performs in these areas. As always, our battery life tests are all run with the display calibrated to 200 nits.
While an early build, it seems that the Nexus 9 is reasonably competitive in battery life but I'm not sure that these results are perfectly accurate. At any rate, efficiency at this stage seems to be par for the course, which should bode well for shipping software. This is a mostly display-bound test though, so we'll look at Basemark OS II to get a better idea for compute-bound battery life.
As one can see, while the battery life of the Nexus 9 ends up on the bottom for phablets and tablets, the overall performance during the test is quite high. We're working on a better comparison for the final review, but this should give a good idea of what to expect in general.
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GC2:CS - Monday, November 3, 2014 - linkThe question is simple, at what power denver matches the A8X ?
If we take the K1 GPU story, we see that Apple has a "bit" lower target for TDP at which the SoC starts to throttle.
Even my two year old laptop is faster than A8X but I didn't saw anyone being interested in that.
chizow - Monday, November 3, 2014 - linkIs your two year old laptop 6-8mm deep and last ~10 hours on 1 battery charge? Then why bother mentioning it.
We see in the review, Nexus 9 actually has slightly better battery life than A8X, so I'd say it matches A8X now at current TDP which is estimated on all these SoCs to be about 4.5W. With the benefit of 20nm it would undoubtedly beat A8X either via more transistors (as Apple did) or higher clockspeeds.
mkozakewich - Monday, November 3, 2014 - linkYeah, what he's saying is that the raw performance doesn't matter if it's not taken in context with the size and battery life and such. He's arguing the same thing as you.
chizow - Monday, November 3, 2014 - linkUh, no except he was comparing two devices in the same class with similar form factors with a 3 year old laptop that is probably 5x thicker with 1/5th the battery life. If he was trying to draw parallels he did an exceptionally poor job at doing so. How is comparing the performance of the Nexus 9 to iPad Air 2 SoCs the same as trying to draw a similar comparison with a 3 year old laptop? Everything that makes the tablet interesting goes out the window on something in that huge clunky form factor.
Alexvrb - Monday, November 3, 2014 - linkHe was clearly exaggerating to make a point. Performance doesn't everything by itself, especially in situations like this. The A8X is a good chip, and it's more efficient than Denver. Give Denver a die shrink and the tables should turn.
chizow - Tuesday, November 4, 2014 - linkHe made a pointless point I guess then, because the A8X and K1 are very close in terms of performance and efficiency to the point I'm not sure anyone could make an accurate assessment based on what we know.
Air 2 has a bigger screen, but the N9's screen is brighter.
Air 2 has a bigger battery, and the N9 has better battery life.
So again, how exactly do you know the A8X is more efficient than Denver?
DERSS - Wednesday, November 5, 2014 - linkJust look at manufacturing norms. Wonders belong to magic farytales, hard reality tells that 20 nm is much more energy efficient than 28 nm.
As result, on heavy load NVidia K1 Denver will fall dramatically, if the load is prolonged. There is no other way, because otherwise battery life under load would be drastically lower than on iPad Air 2.
Alexvrb - Friday, November 7, 2014 - linkSo, before you evangelize Nvidia products, do you actually read the articles?
"As always, our battery life tests are all run with the display calibrated to 200 nits."
Anandtech has been doing this very same procedure for a long time.
tuxRoller - Tuesday, November 4, 2014 - linkThe N9 has essentially the same battery life as the larger screened (larger power draw), smaller battery ipad.
The ipad is also using much lower clocks on their cpu, and their gpu looks to be at least a match to the tk1.
Apple is on 20nm, and that's a big deal, but performance doesn't change things significently.
Pretty dissapointed with this nvidia effort.
Hoping from more with the upcoming cortex a57.
kron123456789 - Tuesday, November 4, 2014 - linkWell, iPad's battery is larger. And Cortex A57 is already here - Galaxy Note 4.