The World's First 3TB HDD: Seagate GoFlex Desk 3TB Review

USB 2.0, 3.0 and FireWire 800 Performance

Seagate sent all three docks for review and I benchmarked the 3TB GoFlex Desk under both Windows 7 and Mac OS X 10.6.4 to get an idea for its performance. The full results are below, but I’ll give you the gist of it here.

USB 2.0 and USB 3.0 docks (left and right)

Over USB 2.0 I got around 30MB/s for sequential reads/writes. That’s 240Mbps, about half of the USB 2.0 spec maximum.

USB 3.0 performance is just awesome, the drive performs just like an internal hard drive. It's a shame that USB 3.0 isn't more ubiquitous because this is great performance not to mention that you get backwards compatibility with USB 2.0 systems. The only issue is you need to make sure you don't lose the USB 3.0 cable since the drive-end of it is not backwards compatible.

I actually got better performance over USB 3.0 than I did with the drive connected via SATA at around 150MB/s for sequential reads/writes. The SATA to USB 3.0 bridge does some additional buffering that may be the cause of the improved performance here. Random performance remained unchanged regardless of what interface I used.

The USB 3.0 cable that ships with the GoFlex Desk USB 3.0 dock. It works in both USB 2.0 and USB 3.0 ports.

On the Mac, without Iometer I had to resort to XBench for the performance numbers. All of these are written via the filesystem but are uncached:

USB 2.0 performance was aroun 15 - 17MB/s while FireWire 800 managed 47.6MB/s for sequential writes and 75MB/s for sequential reads. Copying files to the drive manually I saw very similar numbers over FireWire 800 (53MB/s writes, 78MB/s reads). Note that performance was identical regardless of whether I was using Paragon’s NTFS driver or I formatted the drive in OS X’s native HFS+ file format.

FireWire 800

What this tells us is that, at least compared to FireWire 800 on a Mac Pro, the USB 3 connection in Windows is still the quickest way to write to the drive. There is one more stipulation that I must bring up. Most mainstream motherboards with an Intel chipset don’t give USB 3 controllers enough bandwidth to deliver these sorts of results. I was using a Gigabyte X58A-UD5, but many other boards dangle the USB 3 controller off of a single PCIe x1 lane running at 250MB/s (250MB/s each direction). In these cases you’ll still get better than USB 2.0 performance but you may not see the same numbers I got here.

I wrote about this issue while talking about 6Gbps SATA controllers on Intel motherboards here, but the same problem documented in that article applies to USB 3.0.