Slashdot Mirror
USB 3.0 the Real Deal, SATA 6GB Not Yet
MojoKid writes "HotHardware has posted a sneak peek at a new motherboard Asus has coming down the pipe with USB 3.0 and SATA 6G support. The Asus P7P55D-E Premium has a PLX PCI Express Gen 2 switch implementation that connects to NEC USB 3.0 and Marvell SATA 6G controller chips. With a USB 3.0 enabled external hard drive connected to a USB 2.0 port and then to the board's USB 3.0 port, there were some rather impressive gains to observe. When connected to a USB 3.0 port, the external hard drive was about 5 — 6x faster versus connecting over USB 2.0, with total throughput in excess of 130MB/sec. On the other hand, benchmarks with Seagate's new Barracuda XT SATA 6G drive show little performance difference but a burst rate that is off the charts. According to ATTO, there are slight overall performance benefits to be had connecting the drive to the SATA 6G controller, but the deltas were quite small; somewhere in the neighborhood of 5MB/s or so."
This all sounds like exactly what you'd expect.
The old SATA standard was more than sufficient for the hard disk's max sustained transfer rate, so only burst performance (when everything is presumably coming from the disk's RAM cache) changed with the new SATA. So "SATA 6GB" is working fine, but this disk is just too slow to take advantage of its speed increase.
With USB on the other hand, USB 2 is simply far too slow to handle even the drive's sustained transfer rate, whereas USB 3 is fast enough to handle it.
So the moral seems to be: USB 2 sucks for disks, USB 3 is better and probably sufficient for a typical hard drive, and SATA's still probably better than either (it's not really possible to tell from this article, since the sustained transfer rates are limited by the drive, and they curiously omitted the burst rates for USB).
We live, as we dream -- alone....
You're spot on with the CPU load. The reason Firewire is still so popular, and the reason why Mac users were so up in arms when Apple dropped it from their alu MacBook is that for video and audio there's still no good alternative. I can hang 16 channels of digital audio I/O from the Firewire bus and do live digital mixing on a Mac and run digital effects etc.. There's no way I could do that with USB and expect it to be stable if it works at all. Jobs made a big thing about newer digital video cameras being USB2, but the point is it's offline in the sense that you're transferring data from one hard drive in the camera to a hard drive in the computer - if there's a problem with the USB2 bus the camera can throttle back the data transfer or repeat if necessary. If you're using a tape-based digital format (which is still the mainstream standard in the pro/semi-pro world) then you need Firewire because it will reliably import a full tape without dropping frames; effectively it's streaming rather than just copying, for which I wouldn't trust USB2.
I don't know why the editors didn't include a link to it, but AnandTech has a much better review of the SATA 6G-equipped motherboard and its performance; one that actually gets around to doing real-world tests and not just synthetic tests. It turns out that the 6G Marvell controller is slower than the standard Intel ICH10 controller in virtually all cases. Until someone integrates SATA 6G in to a proper motherboard chipset, it's not just performance limited, it's performance degrading.