The NVIDIA SHIELD Tablet Review
by Joshua Ho on July 29, 2014 9:00 AM ESTBattery Life
As always, battery life is one of the most important aspects of any mobile device, and is crucial to staying mobile. There’s not much introduction needed to this, as it’s rather well understood that more battery life is usually better. The Shield tablet features an integrated 19.75Wh battery.
This device is a tablet first and foremost, so WiFi browsing battery life is important. In this area, the tablet does well. However, it’s a bit strange how the device performs worse than the Nexus 7 (2013). The reason why I say this is that the Tegra K1 is on a far more power efficient process (28HPm), has broadly equivalent battery capacity to screen area scaling, and should have a more power efficient display due to the reduced gamut. However, it could be that Cortex A15 just isn’t as power efficient as Krait and the silicon backplane of the display isn’t as efficient as the one in the Nexus 7.
While normally web browsing tests are enough to cover the relatively low-compute use cases for smartphones, video playback is a significant use case for tablets. Here, we see that the gap between the Nexus 7 (2013) and the SHIELD Tablet narrows significantly, which can probably be attributed to the mostly display-bound nature of this test. Due to the much lower APL average of this test, we see that the Galaxy Tab S line does noticeably better in this test because their AMOLED displays mean that black-heavy content dramatically reduces power draw. This is because a black pixel in an AMOLED display is turned off and doesn't consume power, while an LCD display relies on a backlight so it isn't possible to turn off the backlight for a single pixel without turning off the entire display.
Of course, the Shield Tablet is also designed for gaming. Unfortunately, the Tegra K1 introduces quite a massive amount of dynamic range. While it’s fully possible for the Shield tablet to last 10 hours of continuous use on a single charge, running the GPU at full blast gives battery life similar to a gaming laptop. Realistically, if a game is made for Tegra K1 and truly stretches the GPU to the limit, battery life is only around two and a half hours, assuming display brightness is kept down to 200 nits. Of course, anything less intensive will do much better.
NVIDIA has also made it possible to cap the maximum frame rate and clock speed for better battery life. However, it’s quite clear in this test that the tablet isn’t capable of sustaining peak performance the way the Shield portable was, as the Shield portable sustained around 90% of the first run performance while the tablet sustained around 80% of its first run performance. The Shield Tablet also has noticeably higher skin temperatures, although this was a subjective observation.
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ol1bit - Sunday, October 19, 2014 - link
I know this is old, but my tf201 with a tegra 3 still plays games great! Uninstalling facebook really helped overall speed!UpSpin - Wednesday, July 30, 2014 - link
The Tegra K1 is lacking an on-chip modem, thus it will always be less efficient than Qualcomm processors, which means we'll probably never see this SoC in a smartphone.I think we'll see much more Tegra producs with the K1, because it's really an impressive SoC. But NVidia seems to care less about the typical consumer tablets, more about their own console ecosystem (Shield) and most importantly embedded systems (cars), where NVidia has some huge partners and the Tegra gets widely used. (Tesla, Mercedes, VW, Audi, ...). There they can make more money most probably and don't have to give their IP away for free more or less to remain competive against companies like Mediatek.
fivefeet8 - Thursday, July 31, 2014 - link
The Snapdragon 805 is also in the same boat without an on-chip modem.Knowname - Wednesday, July 30, 2014 - link
who cares about the display? I get mine on Tuesday (preordered from Amaizon and picked no rush shipping fo da bling xD) and 90% of the time I'll be using it to play steam games on my TV.happycamperjack - Wednesday, September 3, 2014 - link
Just got it. The screen is actually pretty good! Much better than I expected. Great contrast, black level, colors. It's more than good enough for a tablet. I got the original Nexus 7. This is much much much better than that! It looks similar to me to the new Nexus 7.sherlockwing - Tuesday, July 29, 2014 - link
No Video playback battery life test?JoshHo - Tuesday, July 29, 2014 - link
It was definitely planned but there wasn't enough time to finish that test. I'll update the review once I have those results.ams23 - Tuesday, July 29, 2014 - link
Josh, how about some additional tests using the battery saver mode? Limiting fps to 30fps and reducing CPU clock operating frequencies should dramatically extend the gaming battery life with very graphically intensive benchmarks.On a side note, I should point out that not only does Tegra K1 have much higher Onscreen performance in GFXBench T-Rex HD test (which is the test used for battery lifetime and a minimum value long term performance data point) compared to most other ultra mobile GPU's, but is also renders with significantly higher [FP32] precision too. According to Oleg at B3D forum, Kishonti uses low precision FP16 shaders in the T-Rex test by default. Mobile Kepler and other modern day PC and console GPU architectures are designed for FP32 precision and not mixed or lower precision.
mkozakewich - Tuesday, July 29, 2014 - link
This! It's horrible to complain about the extra dynamic range like it's a bad thing, and then NOT test the battery-saving features.Limit the CPU such that it runs like the Shield portable, then set the framerate to 30 Hz and run the gaming battery tests again.
(On my Surface Pro, for example, I'll set everything to the lowest possible, about 800 MHz, and I'll get a couple more hours out of it while playing games. High-Performance mode is for when you're plugged in.)
JoshHo - Tuesday, July 29, 2014 - link
Those are definitely planned as well, there were some issues with meeting deadlines so battery life testing had to be cut down somewhat.