The Changing Role of Displays

Thunderbolt carries PCIe and DisplayPort, which enabled Apple to change the role of its display. The Thunderbolt Display is no longer a passive monitor, but it's a full fledged docking station.

Thunderbolt can carry PCIe x4, that's four lanes, which gives Apple the ability to put four PCIe x1 devices in the display itself. Apple chose wisely and included a Broadcom Gigabit Ethernet controller (BCM57761), a FireWire 800 controller and a USB controller. The FaceTime HD and integrated audio codec both use the internal USB controller. Just to be clear, these controllers are present independent of what you connect to the Thunderbolt Display. If you have a Mac with an integrated Gigabit Ethernet controller, hooking it up to the Thunderbolt Display now gives you two GigE ports - and you can use them both in tandem if you'd like. The same goes for FireWire 800 and USB.

Apple doesn't see the Thunderbolt Display as a way to offer more expansion ports, but rather a way to shift those ports to a different location. Chances are you won't need GigE while mobile, but you would like it while at your desk. The same goes for FireWire 800.

What's particularly awesome about the Thunderbolt Display's integrated controller farm is what it does to MacBook Airs. The 2011 MBAs ship with two USB ports and a Thunderbolt port, that's all you get in terms of high-speed IO. With their internal SSDs capable of moving data at up to 200MB/s, you're quickly bottlenecked by the MBA's 802.11n WiFi stack. Had Apple included a Gigabit Ethernet port on the MBA it would ruin the thin form factor. The Thunderbolt Display takes care of all of this. Connect a MacBook Air to a Thunderbolt Display and not only do you get more pixels, but you get more connectivity. Gigabit Ethernet and FireWire 800 are now retrofitted to the MacBook Air. For those notebook-as-a-desktop users who migrated from old MacBook Pros to the 13-inch MacBook Air, the Thunderbolt Display is a must-have. The biggest feature for me is Gigabit Ethernet. For large file transfers 802.11n just doesn't cut it.

While connected you can use the Thunderbolt Display with your MacBook Pro/Air closed or open as a secondary display just like you could with last year's 27-inch LED Cinema Display.


These aren't just ports, they are backed by controllers physically located within the display

The Thunderbolt Display not only adds functionality but it also simplifies cable management as a result. Users who are constantly docking and undocking their notebooks now only have to deal with two cables: power and Thunderbolt. Whereas today I have no less than seven cables plugged into my notebook.

The Limitations

What's missing from the Thunderbolt Display's port repertoire? For starters, there's no analog audio out. While the display does feature a pair of integrated speakers, they don't produce the best sound in the world. Thanks to their diminutive size and unusual enclosure, the speakers don't cover a lot of dynamic range and you can forget about any ultra low frequencies. If you like bass, you still need a sub. Unfortunately there's no way to use the display's integrated audio codec to drive external speakers. You either have to plug a 1/8" stereo cable into your Mac or buy a USB sound card and connect your external speakers to it. In my opinion this is a pretty significant oversight. It either defeats the purpose of the simplified cable setup by requiring you plug in yet another cable into your Mac to use external speakers, or it defeats the purpose of having an integrated audio controller since you need another USB audio controller to get audio out. This is something Apple could've easily solved by just including a 1/8" jack on the back of the display.

Apple has done a great job of including SD card readers on most of its Macs (although I'd love one on the 11-inch MBA, ahem #waystomakeanandhappy). The Thunderbolt Display oddly enough doesn't include an SD card reader. If it weren't for this and the missing 1/8" jack you'd have almost no reason to reach over to your Mac once at your desk.

There's also no USB 3.0 support. While Thunderbolt does enable some very high speed IO, there are still far more USB 3.0 devices than Thunderbolt devices. Not to mention that you likely won't see Thunderbolt enabled flash memory sticks but we already have quite a few portable USB 3.0 drives. USB 2.0 is just ungodly slow today and I'd much rather have Apple introduce USB 3.0 support with its first Thunderbolt Display instead of introducing it with an updated version down the road. The controllers are available on the market today, although it won't be until next year with Ivy Bridge before Apple considers enabling USB 3.0 on Macs.

The final complaint shouldn't come as a surprise, but the Thunderbolt Display just doesn't have enough USB ports in my opinion. The MacBook Pro & Air come with two, while all desktop Macs have at least four. The Thunderbolt Display only gives you three. USB hubs are easy to come by, but I would've preferred to see at least 4 or 5 on the display.

Apple's Thunderbolt Display Testing the Pieces
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  • snow peak - Saturday, July 21, 2012 - link

    I have similar annoying issue here, while playing songs which in iTunes on my new MBA(mid-2012) out via TB display's speaker.
    The audio data stream is routed from MBA to ThunderBolt display, and just one apple's USB keyboard connected to ThunderBolt display.

    You might be interested in trying experiment without external storage attached on TB display, and get same result with mine.

    The symptom is little static noise came with music play at beginning, and then the music gradually merged by static noise after a few of minutes or a couple of hours.

    I think it caused by hardware power ground layout issue, so no confidence apple could fix it via firmware update and no idea if I should return both my new MBA and TB display.

    This is really annoying!!
  • paulrmc - Tuesday, August 7, 2012 - link

    Hi Anand,

    I don't know whether you looked at comparing directly connected USB drives to same drives hooked up to the TB Display. I was shocked today when I found out the difference. I'm using a USB 2.0-connected LaCie 2GB drive as a secondary drive to my dual-SSD mid-2011 Mac mini Server. Using BlackMagicDesign's Disk Speed Test I came to following results:
    - directly connected to the back of the Mac mini: 29MB/sec write, 33 MB/sec read
    - connected to the TB Display: 7.5MB/sec write, 11.7MB/sec read.
    I'm running OS X Mountain Lion 10.8 on the mini, and the tests were repeatable, after fresh power down - reboot cycles.

    Any ideas? Anyone?

    Paul
  • hiscore - Tuesday, August 20, 2013 - link

    I have just discovered the source of my Thunderbolt display distorted audio issue. It is being created by my Drobo which is interfaced through iSCSI. I can replicate the issue every time when moving files to it. Granted the files are moving from my Pegasus array, so I guess there may still be some questions.

    I have been in constant contact with Apple support, Promise support, and Drobo support. Hopefully a fix will be supplied from someone.
  • highscore - Tuesday, December 23, 2014 - link

    Update:
    It wasn't the Drobo.
    I no longer run a drobo and still encounter the issue. The problem seems to occur whenever there is high I/O through Thunderbolt. I have 3 Promise RAIDs and one Lacie 8Big all on one TB bus, with the TBD on the second bus and the problem still occurs. It really just points to a USB buffer issue. The same issue that Anandtech hypothesized in this review.
  • krakago - Saturday, June 7, 2014 - link

    Unfortunately this display is now a dinosaur, and a very expensive one. As of 2014 there are finally more devices and computers appearing with Thunderbolt, but peripherals tend to be very expensive and meanwhile USB 3 has become pretty much ubiquitous. That makes this Apple display unacceptably crippled. If it were cheap that could be overlooked, but it sells for a premium price. I've been looking for a display to use with my Macbook Pro, and comparing the price and features of the Apple offering to their competitors I can't see a good reason to choose the Thunderbolt Display. Apple really needs to bin this thing and bring out a modern version.

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