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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  • JasperJanssen - Saturday, September 24, 2011 - link

    Not every product merits an in-depth review. 1 in-depth equals about 4 or 5 short reviews, and every site has to choose carefully how to spend its time.

    The first time we saw SF2000, there were *massive* reviews. If Samsung would suddenly put out an SSD that is a few dozen percent faster than the current fastest SSD, (and not cost the earth) it'll no doubt get an extensive review. When Apple puts out something very new that could well be the way of the future for the industry as a whole, they get a large review. Makese sense to me.

    And before you jump all over me on that score: Just look at the Sony implementation of Light Ridge on the current Vaio Z. That's a docking station that has everything this thing has (apart from the display) and some more.

    The market as a whole may well not go for integration into displays and integrated power supplies, but Thunderbolt/Thunderbolt-style docking stations seem likely to sweep the world.
    Reply
  • Zink - Friday, September 23, 2011 - link

    +1 top notch video review in every way Reply
  • Sunrise089 - Friday, September 23, 2011 - link

    Agree as well. While I definitely hope the text reviews will continue and receive the most resources, these video reviews are a great supplement, especially with less "numbers driven" products like displays and mobile devices.

    I wish all the CNET, television, etc. reviewers would take a look at this simple, engaging, intelligent review style and adopt it as well. Most reviewers spend way too much time trying to be entertaining and talking down to their audience.
    Reply
  • Anand Lal Shimpi - Friday, September 23, 2011 - link

    The text reviews will continue, this is simply something we're experimenting with to offer an augment :)

    It's always been my opinion that we should treat the readers as equals. It turns out that if you don't treat your readers like idiots then you'll find that you actually attract some really smart people :)

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

    The video was quite good indeed.

    And I like the eye-level-approach. Especially since you had a pretty good balance between talking about the actually interesting bits and still keeping it easy to follow.

    Maybe in some places you might want to slow down just a tiny little bit. ;-)
    Reply
  • Iketh - Friday, September 23, 2011 - link

    NOO!! If anything Anand, talk even faster! Throw it at me at full GigE! I'm a busy man! Reply
  • Constructor - Friday, September 23, 2011 - link

    Just play the video in fast forward then. ;-)) Reply
  • pmcg - Friday, September 23, 2011 - link

    I agree too. What an impressive setup and continuous, cogent presentation. I have never seen a video of Anand but now that I have, I demand more! Should there be an anandtech.tv? Reply
  • jleeworking - Saturday, September 24, 2011 - link

    Wow! nicely done, can we have more of those videos? Reply
  • mymoon - Saturday, September 24, 2011 - link

    Also agreed! Well done Anand on the video review. Felt my time well spent. Reply

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