A Tale Of Two Thunderbolt Storage Devices: Seagate's GoFlex Desk and Western Digital's Thunderbolt Duo
by Brian Dipert on May 13, 2012 7:52 PM EST- Posted in
- Thunderbolt
- Seagate
- WD
- Western Digital
Given that the PCI Express channel of the Thunderbolt interface delivers 10 Gbps of peak bandwidth in either direction, I next decided to see what would happen if I tethered the Seagate and WD drives together.
Granted, Thunderbolt's 8b/10b encoding scheme reduced the effective peak bandwidth to 8 Gbps, i.e. 1 GByte/sec, but that's still substantially higher than the measured throughput of a single Thunderbolt Duo far from that of the Seagate GoFlex Desk. I ran my tests twice, in both cases with the WD Thunderbolt Duo in RAID 0 mode with 32KB RAID block size:
- With the WD drive's upper Thunderbolt port connected to the Mac mini, and the WD drive's lower port connected to the Seagate drive's upper port, and
- With the Seagate drive's upper Thunderbolt port connected to the Mac mini, and the Seagate drive's lower port connected to the WD drive's upper port
After installing a second iteration of AJA System Test, I fired up both copies of the program. Given that the measured transfer rate performance of the WD Thunderbolt Duo in RAID 0 mode was roughly twice that of the Seagate GoFlex Desk, I started the Seagate drive's write test first and, when it was roughly halfway done, got the WD drive going. That way, the two drives' write accesses overlapped for the second half of the Seagate write benchmark cycle, and their read accesses overlapped for the first half of the Seagate read benchmark cycle. Here's the result:
| Combined-Drive Benchmark Results (WD Thunderbolt Duo First In Chain) | ||
| Drive | AJA Write (MBytes/sec) | AJA Read (MBytes/sec) |
| WD Thunderbolt Duo | 239.5 | 241.5 |
| Seagate GoFlex Desk | 135.8 | 135.9 |
| Combined-Drive Benchmark Results (Seagate GoFlex Desk First In Chain) | ||
| Drive | AJA Write (MBytes/sec) | AJA Read (MBytes/sec) |
| WD Thunderbolt Duo | 239.6 | 241.6 |
| Seagate GoFlex Desk | 136.1 | 136.3 |
You can download and peruse the entire suite of test results for yourself, but the short-and-sweet summary is that I discerned no performance degradation from either drive when they were simultaneously doing write or read operations. It's one thing to do the math and conceptually convince yourself that something's possible; it's another thing entirely to see it happen right in front of your eyes. Impressive. Very impressive.
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Death666Angel - Wednesday, May 16, 2012 - link
This sentence is a bit misleading:"a specific RPM at any particular time is dependent on both access requirements and sensed operating temperature." - This would suggest that this HDD runs with varying RPMs. This is not true. One HDD runs with one RPM. However, between the various HDDs among one charge there can be different RPM settings. So one Caviar Green "IntelliPower" runs with 5400 while the next runs with 5900. You will not see one 5400 unit suddenly run at 5900 because the temperatures are particularly low.
bdipert - Saturday, May 19, 2012 - link
Dear Death666Angel, I don't think you're correct. WD has told me on many occasions that the IntelliPower algorithm varies a drive's rotational speed over time as a function of performance demand and operating temperature. And past AnandTech writeups make similar statements:http://www.anandtech.com/show/2385/2
for example
wolfgang123usa - Thursday, July 12, 2012 - link
The real advantage of Thunderbolt should be that it carries power, but special this feature is very limited, as the power pin on the connector is very small and shall carry 10Watts, Sata connectors, USB and other have bigger contact surfaces and/or multiple pins to carry power. The display port adapter was designed for a lot less power then 10watts, that's the current issue with Thunderbolt today. Some details can be found here:http://technology.coolodman.com
When a self powered thunderbolt device is used it works fine and uses only about 22% overhead to encapsulate the PCIe bus, so the speed with fast SSD's like Samsung 830 series is really not bad.
marmot_animal - Friday, July 13, 2012 - link
Two months after this article was written, I find Thunderbolt options at the same phase, quite limited. So I bought the Seagate GoFlex Thunderbolt adapter for $$$ from B&H, plus the cable. Although expensive, it seems for the time being the least expensive approach, albeit a DIY approach, to use raw hard drives, of which I have an expanding collection for my video and audio projects.If my research is correct, there are no official generic Tbolt docks, unlike the common USB3 (and earlier interfaces) docks on Tiger Direct. Although LaCie 2big bays appear to physically allow users to swap raw hard drives, LaCie voids the warranty in doing so. Obviously LaCie discourages a DIY approach and of course favors consumers to procure LaCie's aftermarket harddrive-installed bays. This is less of a diehard obstacle as opposed to WD's Caviar requirement. Conversely, I'm not into opening up enclosures to swap drives. It requires tools, is time-consuming, and is semi-permanent. My preference is to swap raw drives on-the-fly.
At least the GoFlex DIY hacker method works, and I secure the drive on the dock via rubber band technology. I report 'so far so good' with raw drives. I don't know precise speed details as long as I'm able to put the Tbolt bus to use, and it appears faster than any other bus I've used with FCPX. Too many companies try to hijack Tbolt by instilling proprietary constraints. Nevertheless, I find the GoFlex design with its generic SATA interface to be an extremely niche approach because most consumers won't want to seat a raw hard drive somewhat precariously in a dock not designed for such use.
spanading - Saturday, October 6, 2012 - link
Honestly peps,Why are people compairing the two. Yes USB is great if you are conneting things like HHD, Mice, Tablets, and the like, but remember you only have 5Gb in a single channel, one way maximum to play with, while thunderbolt has 20Gb when using both channels. True neither USB 3 nor Thunderbolt would be maxed out by a single HDD, but when connecting several data hungry devices at once, (which with thunderbolt can include monitors, and possible legacy port hubs, if they ever arrive) then USB will show the strain a lot quicker than thunderbolt.
Hence why you need a thunderbolt port? Well if all you are doing is plugging in one HHD over it it is probably overkill, BUT, if you like to have one of those new shiny Ultra books to use on the run but then want a fully fledged PC when you get home, Thunderbolt gives you this potential, but only having to connect 1 cable, rather than 3 or 4. Plus with it being compatible with PCi then you can have expansion cards to further enhance performance with out the need for a completely separate PC. Now before you complain ultra books have low spec CPUs, go and play with one that uses a SSD and see how much speed a traditional HDD sucks up while the system waits for data. As an example, my 2011 Mac book air has a 1.7 GHz dual core i5 with integrated graphic and only 4GB of memory, and on day to day tasks, is faster than my 2011 mac min server with a 2.0Ghz Quad core i7 with the same integrated graphics but 16 GB of RAM. In fact my macbook only struggles when the RAM is all used up, which is not very often .
I guess this is exactly what Dan Neely meant. Good on you Dan, I guess the USB people have not quite grasped the fundamental difference yet.
biswa60 - Saturday, October 19, 2019 - link
Each Thunderbolt port handles 40 Gbps of aggregate bandwidth, consisting of two pairs' worth of distinct 10 Gbps transmit and receive laneshttps://theprintcalendar.com/
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