The ASUS ZenPad S (Z580CA) Review

GPU Performance

Rather than using Intel’s HD series iGPUs, the Atom Z3530 and Z3580 SoCs in both versions of the ZenPad S use Imagination Technologies’ PowerVR G6430 GPU. Since this implementation is identical to the one in the ZenFone 2 it’s not likely we’ll see a large gap in absolute performance. However, the larger chassis of the ZenPad may allow it to dissipate heat more effectively, which could help performance in long-term sustained workloads. It’s also worth noting that the less expensive Atom Z3530 model of the ZenPad S will suffer from reduced performance in GPU heavy workloads due to the 1GHz reduction in max CPU clock compared to the $299 model, as well as the drop in GPU speed from 533MHz to 457MHz.

In 3DMark we actually see a noticeable gap between the ZenPad S and the ZenFone 2. The latter ends up scoring around 2000 points higher in both sub-tests, which leads to an overall score which is also around 2000 points higher. I would mostly attribute this to software differences rather than any issues with throttling, and the next tests will help to confirm that assumption.

The ZenPad S doesn’t perform as well as the ZenFone 2 in BaseMark X’s on screen tests, which isn’t surprising given that it’s pushing 1.6 million more pixels. In the off screen tests we see both devices perform roughly equally, and this is reflected in the overall score. In other reviews, such as my review of the Dell Venue 8 and Venue 10 I mentioned that G6430 is a bit slow compared to the competition at that price point. For a $299 it fits perfectly, and coincidentally a lower clocked version of it is what’s used in the iPad Mini 2 which is also $299.

In GFXBench we again see the ZenPad S performs worse than the ZenFone 2 at its native resolution, but the overall GPU power of the two devices is equal. Like the Venue 8 and Venue 10, the PowerVR G6430 implementation in Atom Z3580 outperforms Apple’s A7 by a significant degree in the T-Rex HD test, but not in any other.

It’s clear from our tests that the GPU performance of the ZenPad S Z580CA is roughly the same as Apple’s iPad Mini 2. Since both devices have the same price, the ZenPad S is right where it needs to be in this regard. Performance in programs running at a device’s native resolution will obviously be slower than the ZenFone 2 due to the ZenPad S’s higher resolution, but I think G6430 provides more than adequate performance to run the display, and is the best you’ll be able to find in a $299 device right now.

NAND Performance

The performance of a mobile device's internal storage can have a significant impact on performance. When any applications are performing reads or writes in the background, a low NAND solution can cause the tasks the user is currently performing to grind to a halt. On top of that, there are fairly obvious implications for the time it takes to move music, movies, pictures, and other media to and from the device.

Both random read and random write speeds on the ZenPad S are very good for a mobile device. In both cases it ends up being the fastest tablet on record.

The sequential read speed on the ZenPad S is good for a $299 device, and the sequential write speed is actually the fastest we've seen in an Android tablet. However, it's disappointing to see that Android devices can now adopt USB 3.0 without terrible connectors by using USB Type-C, yet they still have NAND that won't even saturate a USB 2.0 link in the best possible scenario. Relative to the NAND in other Android devices the ZenPad S performs well, but the speed of eMMC flash memory still leaves much to be desired.