I hooked the eSATA drive up to a PC with a clean install of Windows XP on a 500GB Seagate Barracuda 7200rpm SATA hard disk - pretty much the same disk that’s inside the external eSATA box. Copying a 3GB single file from the internal hard drive to the eSATA disk took one minute five seconds using the SATA controller on the motherboard, compared to one minute six seconds using the Promise PCI controller – almost identical. Reading the same file back from the eSATA drive took one minute 16 seconds using both interface types. I also ran the same test using a 400GB Seagate external hard disk connected over USB 2.0 – the results were two minutes six seconds for the write and two minutes five seconds for the read. So, the eSATA drive is almost twice as fast as its USB cousin.
Of course the characteristic of moving one large file is very different from moving lots of smaller files. I therefore decided to copy 716MB of 8-megapixel digital images from the PC to the drives and back again. This time the eSATA drive was far quicker at writing when connected to the Promise PCI controller than when it was connected to the motherboard’s SATA controller – 16 seconds compared to 26 seconds, while the USB drive took 31 seconds. Reading the digital images back from the eSATA drive took 21 seconds using both the Promise controller and the motherboard SATA controller, while the USB drive trailed at 36 seconds.
So, it’s clear that the eSATA drive is considerably faster than an equivalent USB device, but not by quite as much as I would have expected. But all this really means is that USB 2.0 is a reasonable interface for I/O devices, and it’s also worth remembering that the time differential between eSATA and USB will increase if you’re copying larger amounts of data. With a capacity of 500GB, you could easily find yourself transferring tens of gigabytes at a time to your external drive.
Interestingly, the eSATA drive was hot swappable using the Promise PCI card, but not using the riser attached to the motherboard SATA controller. That said, this probably means that the SATA controller on the motherboard didn’t support hot swapping, whereas a motherboard with integrated eSATA ports will. Either way, you get the controller card in the box, so it’s a bit of a non issue. It’s also good to see that Seagate hasn’t forgotten about Mac users – there are Mac drivers for the controller card also supplied on the CD.
Also in the box you’ll find a stand for mounting the drive on its side, a power brick, a power cable and the all important eSATA cable. I would like to see Seagate start to use an internal power supply and dump the power brick – even though that would make the unit on your desk slightly larger, I think that overall you’d end up with a more convenient solution.