Qualcomm Snapdragon 845: Strong GPU Performance, Less of a CPU Boost

The new Snapdragon 845 SoC is set to star as the Android flagship SoC of 2018, but there’ve been questions about how much of an improvement the new CPU would be compared with older cores. ARM has done an admirable job of improving the performance of its mobile CPUs over the years, and the Snapdragon 845 is another Qualcomm SoC based on a bog-standard Cortex-A CPU rather than Qualcomm’s own implementation of a custom architecture. This time around, the company has gone with the ARM Cortex-A75, the only ARM core to suffer from Variant 3 (Meltdown).

Over at Anandtech, they’ve put a reference smartphone with a Snapdragon 845 through its paces, and come away with mixed feelings. On the CPU side of things, the new SoC isn’t as fast as it was expected to be, possibly because Qualcomm opted to reduce its L2 cache size. The Snapdragon 835 had a 2MB shared L2 on its quad-core “Big” cores, while the “little” cores had a 1MB shared L2. The Snapdragon 845, in contrast, has private L2 caches that are just 256KB and 128KB, respectively. This may have somewhat harmed performance scaling, though the Snapdragon 845 is faster than the 835, especially in floating point performance.

Gaming, however, is a different story entirely. Apple has historically fielded some of the best gaming GPUs, but both the iPhone X and iPhone 8 now throttle so severely, Apple can’t maintain its performance crown — and the iPhone 8 is noticeably worse than the iPhone X in this regard.

Overall, the strong GPU upgrades combined with some modest CPU improvements do establish the Snapdragon 845 as the early leader in Android devices. But the market, as a whole, isn’t sitting still. Samsung has its new M3 products, there’s fresh competition incoming from upstart device manufacturers like Huawei, and we won’t really know how the Snapdragon 845 performs until we see it in shipping products. How an OEM customizes a device has a huge impact on how it ultimately performs. Overall battery life also looks good, with a quad-core cluster drawing a shade less than 4W under load.

It’s not clear what kind of solution needs to be deployed on ARM hardware for Meltdown or whether those fixes were baked into the chip, which is another issue we’ll be keeping an eye on going forward. The performance impact on desktops from Meltdown weren’t very large, but mobile CPUs could be a different story.

On the whole, the Snapdragon 845 looks as though it will present a solid upgrade, particularly on the GPU side of things, with improved efficiency and performance-per-watt. Not bad for a second-generation 10nm SoC, given that such iterations typically don’t deliver overwhelmingly better results.