Last week, we took a closer look at the performance of Qualcomm's Snapdragon 810. Reports of overheating and our own experience with 810-based phones prompted us to dig deeper into the chip's performance under load. After testing multiple devices we found that, yes, the 810 throttles more quickly than comparable chips like Samsung's Exynos 7 Octa, which can slow down performance overall.

Yesterday's LG G4 announcement brought us our first phone based on the Snapdragon 808, which is an architecturally similar but slightly cut-down version of the 810. Where the 810 uses four "big" 2.0GHz ARM Cortex A57 cores and four "little" 1.6GHz Cortex A53 cores, the 808 uses two 1.8GHz Cortex A57 cores and four 1.44GHz Cortex A53 cores. The GPU is also a step down—from an Adreno 430 to an Adreno 418—and there are a few other downgrades here and there, but the CPU is what we'll be focusing on today.

First up, the thermal test. As explained by Primate Labs' John Poole, this is a two-thread test that performs a fixed amount of work over time. Faster processors can spend part of the test idle if they're able to complete that work fast enough. It's still a work-in-progress (Poole tells us that the final version will most likely be a part of Geekbench 4, due out later this year), but it's meant to simulate the kind of work that an actual application might do.

Andrew Cunningham

Andrew Cunningham

Andrew Cunningham

Generally, the 808 is much better behaved than the 810, though its chart is still a long series of spikes rather than the more gradual downward curves we've seen in other phones. It spends far more time at its top-rated speed of 1.8GHz and far less time throttling down to the low-power, low-performance "little" cores. And while the 810 throttled more and more as the test ran longer, the 808 can still reach speeds between 1.4 and 1.7GHz even after the test had run for 15 minutes.

What does this mean for general performance? For quick things—get your phone out, check your e-mail, put it back—not a whole lot. These processors are designed around that kind of "bursty" usage. For anything where the phone is busy for more than a minute or so, things like games or long browsing sessions, the 808's stamina and consistency will come in handy. Once the 810 warms up, its performance drops off quite a bit. This chart demonstrates the difference; the Snapdragon 810 in the Flex 2 falls off a cliff while the 808 barely moves.

Andrew Cunningham

Andrew Cunningham

Remember that our Snapdragon 808 sample size is one—a single phone from a single OEM. But years of phone testing have shown SoCs to act mostly the same in similar products. Just as we'd expect the 810 to have some heat issues in any phone it's in, based on the results from the G4, we think the 808 should generally behave more like Qualcomm's older SoCs have behaved. It's not at the cutting edge of performance, but hey, at least it's not at the melting edge.

Ars Reviews Editor Ron Amadeo will be doing more performance and battery life tests on the G4 and publishing them along with our main review. That's when we'll know how much GPU performance the 808 gives up relative to the 810 and whether the G4 can deliver better battery life than last year's somewhat disappointing G3. Look for it in the coming days.