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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  • mcturkey - Friday, September 23, 2011 - link

    I guess I really don't understand why they can't just make a non-integrated docking station. Use Thunderbolt to connect it if need be, but making it part of the display seems to just add a very unnecessary expense increase if you find yourself needing a new monitor or different/more/better ports in the future.
  • Constructor - Friday, September 23, 2011 - link

    As far as I'm aware there are already multiple external PCIe slot housings and other adapters on the way which will effectively serve that purpose.

    And all of them will be usable with any Mac or PC which has suitable PCIe drivers for the respective ports, so Thunderbolt can indeed provide the long-missing "universal dock".

    The complication may be that these drivers should be able to survive hot plugging if you want to avoid having to reboot the machine every time you (dis)connect such an external box (or possibly risk a blue screen / kernel panic otherwise).

    Apple just chose to make one specific bundle product; They're leaving all the other possibilities to third parties so far. Once such alternatives are on the market, it's simply your choice.
  • SameerRamesh - Friday, September 23, 2011 - link

    My strong gut feeling suggests that apple will bring only USB 3.0 ports to all their next-gen Macs. Why?
    Intel's IVB chipsets have native USB 3.0 support. So apple needn't do any extra work there. Furthermore, not adopting an industry standard is a loss. Adding to that, they haven't gone against USB 3.0 now, have they?
    Why only USB 3.0 in the next-gen Macs? That's Apple's style!
  • Constructor - Friday, September 23, 2011 - link

    Current Intel chipsets don't have USB3 on chip, so it would take external USB3 controllers to add them to a Mac.

    The problem is that such external controllers consume precious PCIe 2 lanes which are comparatively scarce with the mobile Intel CPUs. I've not checked the data sheets, but there may simply not be enough PCIe 2 lanes with a mobile Intel CPU to supply both a full-speed-capable external USB3 controller and the Thunderbolt controller at the same time.

    Given that choice, I'd say Thunderbolt is the far better option of the two (not least since you can connect USB3 externally through it, but not vice versa).

    Desktop CPUs are less constrained, so the iMac and the Mac Pro could have both at the same time even with the current CPU generation (through PCIe plugin cards, if need be).

    But I expect Apple to make the jump with the upcoming CPUs which simply provide them on chip with nothing to sacrifice for it.
  • JasperJanssen - Saturday, September 24, 2011 - link

    Ivy Bridge generation Macs will obviously have USB3. Presumably enough of them so that there are no USB2 ports left, as Apple does not like mix and match. And when the Macs have USB3, the display will get it too.
  • quiksilvr - Friday, September 23, 2011 - link

    Can you use this Thunderbold Display on another Thunderbolt computer that isnt Mac?
  • Anand Lal Shimpi - Friday, September 23, 2011 - link

    Theoretically, yes. We won't know for sure until we see the PC implementations of Thunderbolt but according to Apple if a PC vendor were to integrate Thunderbolt and fully follow the spec the Thunderbolt Display would work.

    Take care,
    Anand
  • the goat - Friday, September 23, 2011 - link

    Somebody already solved this problem decades ago. It is called a laptop docking station. All those cables you are complaining about stay plugged into the docking station.
  • Parhel - Friday, September 23, 2011 - link

    That's what's confusing me about this too. Why is this better than, or even as good as, a docking station?

    With my docking station, I just have to put my laptop on it, and I'm connected to wired network, monitor, mouse and keyboard. I could add another monitor (2 dual link DVI ports), speakers, a printer, and I believe 4 USB devices to that.

    I have one docking station at home, one at the office. The dock for home cost me under $100, and it's compatible with both my laptop and my wife's. This seems like a step down from that.
  • HMTK - Friday, September 23, 2011 - link

    If you wan't a razor thin laptop like a MBA there's no room for a docking connector in the laptop. That's probably the main reasons why Apple makes this thing. For their customers it's good.

    Personally I prefer a docking station exactly for the reasons you stated. I would like to use a generic docking station that's not USB though because now docking stations can only be used with a limited number of machines and there's no compatibility between brands.

    Laptop makers are being forced by the EU to make compatible power bricks. Why not do the same for docking stations? Or force them to make a single connector for data and power that's also compatible with a power supply only?

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