Thunderbolt Performance

The Eagle Ridge Thunderbolt controller is home to two Thunderbolt channels, each one is good for up to 10Gbps in either direction (up or downstream). That works out to be 20Gbps of bandwidth per channel or 40Gbps aggregate between the two. You can only send two channels worth of data down a single Thunderbolt cable, so there's no point to having more than two from a performance standpoint unless you have more than one port on your system.

If DisplayPort and PCIe traffic are indeed carried on separate channels, then the Thunderbolt Display by itself is eating up around 70% of the bandwidth of a single channel on its own (2560 x 1440 x 32bpp x 60Hz with 8b/10b encoding > 6.75Gbps). That leaves 10Gbps in each direction for PCIe traffic. If we look at our benchmarks from the previous section we see that we can hit just under 2Gbps with all of the auxiliary interfaces (GigE, FW800, USB2) running. Given our previous investigation with the Promise Pegasus we know that 8Gbps is feasible there as well. It's possible, that with everything running at once, we could actually run into bottlenecks with Thunderbolt.

To find out I ran a few tests. First I needed a baseline so I threw four SF-2281 SSDs into the Pegasus R6 chassis and configured them in a RAID-0 array. I ran a 2MB sequential read test (QD=16) and measured 909MB/s from the array. This value was obtained without the Thunderbolt Display connected, only the Pegasus R6.

Next I connected the Thunderbolt Display directly to my test MacBook Pro, and then connected the Pegasus to it. I repeated the test, this time getting 900MB/s. Thankfully the presence of the Thunderbolt Display doesn't seem to impact the max data rate I can get from the Pegasus.

For my third test I added a Gigabit Ethernet transfer from a file server to a local SSD using the GigE port on the display. During this test I was also playing back music using the Thunderbolt Display's internal audio codec and speakers. I re-ran the Pegasus test and got 855MB/s.

For my final test I re-ran the third test but added a FireWire 800 to USB 2.0 SSD transfer, both connected to the Thunderbolt Display. I also fired up the FaceTime HD camera on the display using Photo Booth and left it on during the test. The final performance score from the Pegasus was 817MB/s.

Apple Thunderbolt Display Performance

With everything running Thunderbolt performance took a 10% hit. Note that the standard Pegasus configuration isn't able to hit these data rates to begin with, so unless you've pulled out the 12TB of storage and stuck in your own SSDs you won't see any performance drop.

What this does tell me however is the ultra high end users that are looking to daisy chain multiple Thunderbolt storage boxes together may not want to do so. I only have a single Pegasus R6 on hand, but I'm guessing there will be significant performance drop off after the first box. Not that I'm complaining about being able to push nearly 1GB/s over a $49 cable from a notebook, I'm just trying to give a heads up to those who may have aspirations of even higher performance.

Testing the Pieces Display Testing - Color Quality & Uniformity
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  • Anand Lal Shimpi - Friday, September 23, 2011 - link

    We do not accept payment for any review, this one included.

    Take care,
    Anand
    Reply
  • Anand Lal Shimpi - Friday, September 23, 2011 - link

    I needed to start somewhere :) The next video review won't be an Apple product ;) And we do try to take great photos of everything we review when possible. I believe some of the best photos to-date have been of Android smartphones imho done by Brian Klug.

    Take care,
    Anand
    Reply
  • Aikouka - Saturday, September 24, 2011 - link

    It's a good review overall, but I do have a comment or two:

    - When switching to a completely different view, I would recommend using a quick transition such as a fade. It's rather jarring to just suddenly switch to a completely different picture like that.

    - If you'd like to make video reviews a bit more common, it might be worthwhile to consider a slight site change to make them a bit more accessible. Some sort of thing (tabs, buttons, etc.) near the top to switch between a text review and a video review.

    I'm trying to figure out though... did you build that entire stage area for the review, or is that a blue screen behind you? The shadows on the lettering made me wonder.
    Reply
  • G-Man - Friday, September 23, 2011 - link

    I'm guessing they make the extra effort on Apple-products, simply because A LOT more people read those articles than the odd generic laptop review.

    If you've been following Anandtech for a while, you will see that they recap and explain (basic) technology and concepts in Apple review, because more people read them, and less tech savvy people read them.

    So it's only natural for them to put extra effort into Apple-reviews.

    PS: Anand, LOVE the video review. Please keep making them! :)
    Reply
  • gevorg - Friday, September 23, 2011 - link

    Anandtech just loves Apple products, hence the special treatment. :) Reply
  • MrX8503 - Friday, September 23, 2011 - link

    Maybe you're the fanboy. Its a good review just like any other, accept it. Reply
  • KoolAidMan1 - Monday, September 26, 2011 - link

    B3an is definitely the fanboy, there is massive bias when he posts in DT threads Reply
  • KoolAidMan1 - Friday, September 23, 2011 - link

    Part of it is that Apple products generally photograph better than others. It is hard to polish a turd, no matter how well you frame or light it. On the other hand, a beautiful object can photograph well under most circumstances.

    As for effort into reviewing Apple products, it is generally because they are on the leading edge of physical interfaces, form factors, and technologies. Three years after the debut of the Macbook Air and now there is a massive push from other companies to deliver comparable machines.

    The reasoning behind the Thunderbolt review is that it points to a very probable future for PCs, one in which your laptop is also your main computer. One option will be to have a laptop that plugs into a Thunderbolt hub (which may or may not be integrated into a display) which has all of your external devices and other things such as a dedicated desktop GPU, etc etc.

    It is interesting how much anti-Apple bias there is here. I'm typing this on my PC but I"m not blind to how vital Apple is to the industry.
    Reply
  • seapeople - Friday, September 23, 2011 - link

    You're comparing the reviews Anand does himself to what some of the other editors do for cheaper/less advanced products. Look at Anand's SSD reviews (especially when its for a new/unique controller) and you'll see the same detail. Reply
  • Kristian Vättö - Saturday, September 24, 2011 - link

    And at the same time, many SSD reviews consist of just benchmarks and a small introduction. Take for example the Samsung 830 SSD review, it's not that massive, mainly because Samsung isn't that big player. Reply

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