USB 3.1 Tested: Performance On MSI's X99A Gaming 9 ACK

Hands-On With USB 3.1

Each year, we make our pilgrimage to Las Vegas, Nevada for the Consumer Electronics Show. And each year, we’re bombarded with technologies, architectures, mock-ups unlikely to appear on store shelves and products that started selling six months ago.

Our meetings go on for a week straight. When they're all said and done, our heads are crammed full of specs and launch dates. Truly, only the most special devices elicit an, “Oh yeah—I remember that!” But I believe the great volume of writing already devoted to USB 3.1 demonstrates the tech press’ unanimous recognition of a standard you’re bound to encounter sooner or later.

Maybe you didn’t realize it’d be this soon, though. During the show, USB 3.1 was on display using ASMedia’s ASM1142 PCIe-to-two-port USB 3.1 controller and ASM1352R USB 3.1-to-SATA 6Gb/s developer board. We got our hands on the demo hardware needed to test the standard’s early performance.

Testing USB 3.1: The Hardware

The ASM1142 is integrated onto MSI’s X99A Gaming 9 ACK motherboard. As far as we know, this will be the first platform armed with ASMedia’s latest, exposing two Type A ports on the I/O panel. As a chipset, X99 didn’t offer much in the way of innovation, so add-in extras like the ASM1142 go a long way in giving high-end systems some degree of differentiation beyond the usual bundled Wi-Fi, PCIe switches and overclocking aids.

MSI says the controller is attached to the PCH via two lanes of second-gen PCI Express, yielding up to 1GB/s of peak throughput. Yes, there are several peripheral configurations that’d result in contention for the Platform Controller Hub's available resources. X99 exposes 10 SATA 6Gb/s ports, six USB 3.0 ports and gigabit Ethernet natively, all behind a four-lane DMI 2.0 pathway to the host processor. It’s not difficult to jam up…if you try. This first implementation of USB 3.1 is storage-oriented though, and in applications where you’re moving lots of information to or from an external drive, it’s unlikely that other subsystems are getting hammered.

A cable connects the developer board through its Micro-B jack. Notice the lack of reversible Type-C ports in this equation. Although Type-C is commonly associated with USB 3.1, it isn’t necessary in order to realize the standard’s performance benefits, just as the presence of Type-C doesn’t automatically indicate USB 3.1 transfer rates.

The developer board is a straightforward affair, consisting of ASMedia’s ASM1352R controller, two SATA connectors, power input and a handful of jumpers. We’re attaching a pair of 480GB Intel SSD 730 drives, which get striped and formatted at the push of a button.

The Experiment

We’re exploring performance on three fronts today. First, we’ll use the ASMedia development board with the two Intel SSD 730 drives in a striped array, comparing transfer rates of ASMedia’s controller against Intel’s native USB 3.0 interface and a VIA Labs add-in controller also present on the X99A Gaming 9 ACK motherboard.

Then, we’ll add numbers using one of the fastest USB 3.0-capable thumb drives you can buy to see if the new standard offers any benefit to those of you with current-gen USB hardware. The final test will compare CPU utilization during file transfers to gauge whether USB 3.1's greater throughput is any more or less compute-intensive than USB 3.0.