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

The Fastest USB 3.0 Thumb Drive And CPU Utilization

At least for now, USB 3.1-capable client devices are non-existent. And it’s going to be hard to sell enthusiasts on the merits of early adoption without anything to attach. That’s why we took the fastest USB 3.0 thumb drive in our lab, Patriot’s 256GB Supersonic Magnum, and hooked it up to three different controllers.

The same 36.7GB of large media files were loaded onto the Supersonic Magnum and then written off to a 40GB RAM disk. Connected to ASMedia’s USB 3.1 controller, this task took 148 seconds. Intel’s PCH-based USB 3.0 logic was slightly slower at 150 seconds. VIA’s single-lane, four-port VL805 posted a 158-second result.

We’re in that territory where the performance delta is measurable, but not significant enough to warrant a strong opinion. Still, it’s nice to see a third-party controller tacked on through PCI Express out-mode Intel’s integrated USB 3.0 solution, if only by a couple of seconds.

Patriot’s Supersonic Magnum is an eight-channel thumb drive rated for 260MB/s reads and 160MB/s writes. That extra bit of read performance gave ASMedia’s USB 3.1 controller a slight advantage in the previous chart. But a lower ceiling puts ASMedia and Intel at the same level when it comes to writing 36.7GB of information to the thumb drive.And yet, both controllers continue to trounce VIA’s alternative.

CPU Utilization

Alright, so even the fastest USB 3.0 thumb drives don’t get much benefit from a USB 3.1 controller. What other performance-oriented could the new standard offer? Going back to the ASMedia developer board (which, yes, means waiting for USB 3.1-capable client devices), we wanted to look at CPU utilization during a big file transfer.

Interestingly, Intel’s USB 3.0 controller writes to the array of striped SSDs at about 220MB/s, completely utilizing one logical core on our Core i7-5930K, giving us roughly 11% total utilization. Meanwhile, the ASM1142 realizes ~500MB/s and monopolizes a fraction of one logical core, returning 5% total utilization.

USB 3.0 transfer: 11% utilizationUSB 3.0 transfer: 11% utilizationUSB 3.1 transfer: 5% utilizationUSB 3.1 transfer: 5% utilization

So even if there aren’t any USB 3.1-enabled devices on the market yet, it appears that there’s a reason other than throughput to anticipate greater availability. After all, the only thing better than a faster interface is more speed and improved efficiency.