Performance Analysis

While USB 3 claims speeds of up to 5Gb/sec, we were pessimistic due to the relative infancy of the standard. Our testing soon showed our cynicism was well founded, although not without some very encouraging signs.

Using our Indilinx-powered 128GB Corsair X128 SSD and the Asus U3S6 card, we should have seen results identical to those of SATA 3Gbps, where the limiting factor is the drive and not the bus. Sadly, this wasn’t the case, with the drive performing a fair margin slower than on SATA 3Gbps. Average read speed across the drive dropped by 40MB/sec (320Mb/s) by switching to USB 3. While average write and burst speeds weren’t as badly hit, the dip in performance from switching to USB was obvious.

Bizarrely, the Sharkoon USB controller card was even slower than the Asus by a margin of roughly 50MB/sec (400Mb/sec) across the board in HDtach. We’re not sure why this is – both cards use the same USB 3 controller chip, and the 1x PCI-E connection of the Sharkoon provides 500MB/sec of bandwidth, which is far more than our 140MB/sec SSD required. Not all USB 3 cards are created equal, it seems. Possibly the Asus card boasts superior firmware, or else the 2x PCI-E connection does offer a benefit, but we can’t be sure which.

These dips in performance in HD Tach when switching from SATA 3Gbps to USB 3 translated into our sequential file tests using FC-Test. The Asus USB 3 card delivered performance that was consistently 30 per cent slower than SATA 3Gbps on write and copy tests. The Sharkoon USB 3 card was slower still. Interestingly though, read speeds were much closer to SATA 3Gbps speed for the Asus, which delivered a sustained read speed of 186MB/sec when reading our 1.6GB ISO file pattern. This was an enormous improvement over the 32.6MB/sec sustained read speed of the same drive when we switched it to USB 2.

Should You Upgrade Now?

While it’s a disappointment not to see USB 3 delivering its full potential just yet, the jump up from USB 2 is still nothing short of astonishing - it’s just as important as the switch from the original USB to USB 2 back in 2000. Our testing shows a fivefold increase in transfer speed in comparison to USB 2; considering this is without any file transfer protocol optimisations, this bodes very well for the future of external storage.

We were also pleased to find that the ever-important backwards compatibility of both the USB 3 ports and our USB 3 device worked flawlessly. USB 2 devices were instantly recognised when they were plugged into a USB 3 port, and our USB 3 disk caddy had no problems running at USB 2 speeds via a USB 2 connection.

We were concerned at the disparity between the two USB 3 controllers we tested though. Both were tested using identical hardware, in the same PCI-E 2.0 slot, and even use the same host controller chip and driver, yet the Sharkoon was much, much slower than the Asus. This seems even odder when you consider that it’s also the more expensive card of the two, selling for £41.40 (inc VAT) in comparison to the Asus card which costs between £25 (inc VAT) and £30 inc VAT).

Stock of the Asus is due at the end of December, and we even contacted Asus to check of those pre-order prices are correct, which they are. Asus told us that the only reason the U3S6 card exists is so that Asus customers that bought one of the first P55 motherboards wouldn’t feel the need to ditch that in order to get all the USB 3 and SATA 6Gbps goodness of the motherboard updates it’s releasing.

While we’re not sure why the Sharkoon is slower and more expensive than the Asus card (which also has a SATA 6Gbps controller), what we can say is that if you’re interested in jumping on the USB 3 bandwagon early, there's no real reason to wait, and the Asus card is certainly the one to go for. As for the Sharkoon USB hard disk caddy, £51 (inc VAT) is roughly the right price for this type of device, and it worked perfectly well over either a USB 3 or USB 2,

Final Thoughts

While our first foray into USB 3 might ask as many questions as it answers, it’s clear there’s an enormous amount of potential in the new standard. For ages USB devices and storage have been the ponderous drawback to much of our technology, especially for those with extensive external storage, and USB 3 is undoubtedly an important and arguably vital step forward considering our ever increasing demand for more storage.

If it’s able to reliably deliver the performance it claims, USB 3 could even become a rival to traditional internal connectors such as SATA. It could provide all the power and data bandwidth required for a full-sized 3.5in hard disk over a single cable, which will help those that always run out of spare mains plugs behind their PC.

Whether USB 3 will take over in this regard remains to be seen of course, but what is guaranteed is that USB 3 has arrived, and it’s already massively quicker than its predecessor. Things will only get faster as hardware and software developers get to grips with its super-speed bus, and it’s going to offer more flexibility via its greater ability to deliver power too. One thing’s clear now though: we’re going to need a faster flash drive.