The Performance of Kindle Fire HDX
Texas Instruments has been a big player in silicon for longer than most realize, but its presence in the last few Kindle Fires hasn’t been completely successful. TI’s silicon wasn’t necessarily underpowered, but for whatever reason, the user experience was full of hesitation and inconsistency. Among Android tablets, those traits aren’t unique to the Kindle Fires; the graphically rich interface was particularly taxing on TI’s SoCs. In the wake of TI’s departure from the consumer SoC space, Amazon has a new partner for the updated Fires; the results are smoother than we’ve seen in many other similarly specced slates.
Qualcomm’s Snapdragon 800 line is no stranger to us, and the number of design wins it has achieved is evidence of its strengths. The approach Qualcomm has long taken is to integrate as many specialized components into the die, working with the device manufacturer to enable the best use of the hardware through software optimizations. That ensures that the CPU is never being tasked with performing imaging manipulations that an image signal is better suited for or noise cancellation better suited for a DSP.
In this case, the clock speed is advertised at 2.2GHz, though it’s more precisely 2.15GHz, just as the 2.3GHz model is more precisely 2.265GHz. That the numbers are different rounded up is not the important part; it’s that the Snapdragon 800 variant that Amazon selected was binned for performance and power characteristics. Higher clock speeds require additional voltage, and higher voltage means shortened battery life. By opting for a chip with good power characteristics, you’ll end up improving battery life without necessarily sacrificing performance.
Objective benchmarks give us hard data on how well Amazon has utilized the Snapdragon 800, but even high-scoring devices can fall short in the subjective experiences that truly define a device. But before we get to the subjective observations, let’s talk about synthetics. We’ll kick off with our usual set of browser benchmarks. These tests stress the CPU and a few other components and are all run on the latest Chrome for Android build to make them suitably comparable. Getting Chrome onto the Kindle was something of a feat, but since the stock experience isn’t Chrome, I’m also including the performance of Silk, the stock browser.
That the HDX outpaces nearly all the competition while running Chrome is a testament to the work Amazon’s engineers have done under the hood. That the Silk browser was able to keep pace and edge out a win is the real surprise. HDX buyers aren’t sacrificing browser performance by not using Google’s browser of choice, just Chrome’s features. The overwhelming advantage by the Snapdragon 800 in the HDX over the Note 3 may be related to thermal dissipation. Though clocked lower, the HDX may keep its Krait cores at a high frequency for a longer amount of time than the Note 3, without as much concern for overheating.
The story gets a bit murkier when you look at the other benchmarks. GeekBench 3 has served as a good gauge of CPU and memory performance. Here, the HDX falls a bit behind in single-core benchmarks, trailing the Note 10.1 and Note 3 in all but memory tests. We’ve begun masking the benchmarks that are being run, so the results from both the Note 3 and the Note 10.1 are not being optimized for in software. The numbers do indicate that the clock speed advantage of the Note 3 translates to higher benchmark scores here.
In the graphics front we have impressive performance and some sign that the GPU is also modestly clocked relative to the Note 3’s Adreno 330. The T-Rex HD scores are solid, though not class leading. The Egypt HD scores are substantially lower than the Note 3’s, though not so bad as to make gaming unpleasant. I suspect that the same restraint Amazon showed with the CPU clock speed is being shown with the GPU. In game, though, performance is impressive and smooth in even graphically intense titles.
And lastly, we have our storage test, AndroBench. The HDX shows no great deficits, though its write speeds are a bit low across the board. It’s unclear how much this will matter in daily use; the read speeds are sufficiently high to pose no limitations there.
Silicon performance and battery life are tied tightly together, and with the slight decrease in clock speed there’s potential for some serious battery life. Thankfully, the potential is realized. Amazon claims 11-plus hours of battery life while watching video, and after putting the device through its paces for a few days, I don’t doubt it. The balanced approach of reasonable clock speeds and tighter thermal control without sacrificing performance seems to have paid dividends in battery life, too.