USB 3.0 may be the future, but it may still have room for improvement. Per Techworld, the upcoming port technology may be hard pressed to surpass current technologies like eSATA.
The test comprised plugging Freecom’s USB 3.0 external drive, the XS Hard Drive 3.0, into a mainstream dual-core notebook using the company’s new USB 3.0 Express Card notebook add-on.
Throughput was derived using a simple calculation based on how long the drive took to copy and paste a large number of video and image files to and from the laptop, replicating how the drive will actually be used in the real world for functions such as directory backup.
The Freecom XS operating in USB 2.0 mode managed an average throughput of 18.7MB/s for reads and only 11.1MB/s for writes, well below the theoretical maximum of USB 2.0 but in line with real-world transfer speeds on a mid-range laptop.
The same drive in USB 3.0 mode raised this to 36.6MB/s for reads and about the same or slightly slower for writes, although this fluctuated considerably for reasons that might relate to the supplied NEC driver. Still, there seems to be a relative difference which will depend on a range of factors including overall system performance.
The tests concluded that USB 3.0 offers even notebook users a handy though not spectacular speed boost compared to USB 2.0 of around two-three times. However, when pitted against an eSATA drive from LG, the interface port for which is found on many high end notebooks, the results were less clear cut.
Copying the test files to an external LG eSATA drive achieved throughputs of 32.5MB/s for reads, and 29.7MB/s for writes, not much slower than USB 3.0 on this hardware. In some cases, it even matched the USB 3.0 drive.
Freecom engineers agreed that USB 3.0 would be held back by a number of bottlenecks on today’s systems, especially laptops which typically use slower internal hard drives. Desktop systems which can use the company’s faster PCI Express Card interface would fare better, they said.
USB 3.0 will start to shine when paired with forthcoming SATA 3.0 or even SSD drives, faster CPUs able to keep up with the dramatically higher data throughtputs, integrated USB 3.0 ports that don’t need slow interfaces such as Express card, and possibly also better drivers and chipsets.
One reply on “USB 3.0 underperforms in notebook tests, bottlenecks cited”
I think your suggestion that USB 3.0 drive thruput might be hampered by the drive itself, is quite good. SATA laptop drives are running in the 60-MB/s range, when connected directly to a system buss properly. But add the SATA to USB conversion hardware, and whatever caching scheme is in the drive-case itself, and performance is going to be cut almost in half. These problems are not laptop related, do the test on a desktop, with the same drive/case, and you'll get roughly the same performance as in the laptop test.