When Apple launched the iPhone XS with its A12 Bionic chip, it made some fairly significant claims for the performance improvements over last year’s iPhone X.
In particular, the company said that the two high-performance cores are up to 15% faster while using up to 40% less power, and the graphics processor is up to 50% faster. ‘Up to’ numbers can often be very misleading, so Macworld decided to carry out some careful benchmark tests …
To carry out its tests, Macworld tried to eliminate as many variables as possible, so that it was getting as close as you can to measuring pure performance.
We run every test multiple times, allowing the phone to cool off between runs. Tests are run in airplane mode where possible and with no other applications loaded. We do all of this to help eliminate inconsistencies and allow each device the opportunity to achieve its best result.
The site found only minor differences between the iPhone XS and XS Max, except in battery-life. There, the larger model lasted around 20% longer as you’d expect from the larger battery.
Geekbench 4 is the most popular benchmark test, as it is not only available on a wide range of platforms, but is calibrated to be broadly comparable between mobile devices and computers.
The iPhone XS’s single-threaded performance should have been 15% faster than the iPhone X, and the tests showed it to average 13% faster.
That [also] helps contribute to a very small improvement in multi-core performance, but since the four energy-efficient cores aren’t really any faster, the difference is minimal.
Geekbench’s GPU test should have shown a 50% improvement to match Apple’s claim, and the average was a little under 40% faster than the iPhone X.
3DMark Sling Shot
One surprise was that the 3DMark Sling Shot benchmark – another popular GPU performance test – showed virtually identical speeds to the iPhone X. MacWorld’s Jason Cross has a theory about that.
What happened to the “up to 50 percent” GPU speed improvement of the A12 Bionic? Well, it’s quite possible that this test, with all of its large art assets, is entirely bottlenecked by memory bandwidth and cache performance rather than the GPU’s ability to perform computations.
That theory is somewhat validated if we run the older Ice Storm Unlimited test [which] runs around 18 percent faster on the new hardware.
Which brings us back to one of the points I frequently make about benchmarks: the performance they show may not be reflected in real-world usage. That’s partly because there are way too many variables, and partly because, for many tasks, the performance difference is going to be imperceptible.
But for what it’s worth, Macworld found that the iPhone XS came somewhat close to matching Apple’s claims, while not hitting the top end of them. We’ve also seen the iPhone XS Max beat out the Samsung Galaxy Note 9 in an app launch speed test, and it also earned DisplayMate’s award for best smartphone display.