The Apple Thunderbolt Display Review
by Anand Lal Shimpi on September 23, 2011 2:56 AM EST- Posted in
- Displays
- Mac
- Apple
- Thunderbolt
- Thunderbolt Display
Multi-monitor with the Thunderbolt Display
The Thunderbolt Display has a single Thunderbolt port for daisy chaining additional devices. Each Thunderbolt port can support 7 additional devices, which means 6 devices once you connect the Thunderbolt Display. These devices can be anything Thunderbolt, however you cannot connect a DisplayPort monitor to the Thunderbolt Display directly. If you want to connect another monitor directly to the Thunderbolt Display it must be another Thunderbolt Display. To understand why, we need to look at the architecture of a Thunderbolt controller.
This is the first Thunderbolt controller Intel introduced, codenamed Light Ridge:
You see it has four Thunderbolt channels and two DisplayPort inputs. It also has a single DisplayPort output as well as a DisplayPort passthrough option. What's the difference? If there are only two devices in the chain, the computer and a DisplayPort monitor, you can use the DisplayPort passthrough option bypassing the majority of the logic entirely. This is how the 2011 MacBook Pro can connect directly to a DisplayPort display. Put a Thunderbolt device in between those two devices and you can no longer use the passthrough mode. You have to send a Thunderbolt signal to the Thunderbolt device, and it can then extract the DisplayPort signal and output it. Simply passing DisplayPort through won't work.
I originally believed Apple used the smaller Eagle Ridge controller in its Thunderbolt Display, but now believe that to be incorrect. Upon closer examination of our dissection photos it appears that the 27-inch panel is driven by an embedded DisplayPort (eDP) connection. If I'm right, that would mean the DisplayPort output from the Light Ridge controller is routed to the eDP connector in the display. With its sole DP output occupied by the internal panel, the Thunderbolt Display cannot generate any more DP signals for anything connected directly to its Thunderbolt Port.
If you connect a Mac to the Thunderbolt Display what is sent is a Thunderbolt signal. DisplayPort is broken off and sent to the display but there's no way to propagate an additional DisplayPort signal to any other non-TB displays in the chain. The output on the Thunderbolt Display is literally a Thunderbolt output, it can't double as DisplayPort.
However, if you connect another Thunderbolt device that uses Light Ridge you can split any additional DisplayPort signals out of the chain. In other words, if you connect the Thunderbolt Display to a Promise Pegasus you can then chain on another DP panel. If you own a 27-inch Cinema Display and were hoping to add the Thunderbolt Display to it on the same Thunderbolt chain, you will need another TB device in between.
There are also the obvious GPU limitations. The 13-inch MacBook Pro only supports two displays (Ivy Bridge will up this to three). If you manage to connect two to the 13 however, Apple will just blank the display on the notebook and drive the two external panels. The MacBook Air is a different story. Not only does it only support two displays, but the Eagle Ridge controller only has a single DisplayPort input so you're not driving more than one external display via a MBA no matter what you do.
I tested multimonitor functionality with a 27-inch LED Cinema Display as well as a second Thunderbolt Display. In the case of the Cinema Display, as expected, I couldn't get video out of the port on the Thunderbolt Display. Connecting the Thunderbolt Display to a Promise Pegasus and then connecting a Cinema Display to it worked however. I also woke up the MacBook Pro's internal display and confirmed that I could get all three functioning simultaneously. There's a definite slowdown in UI frame rate with two 27-inch panels being driven by the MacBook Pro's integrated Radeon HD 6750M. It's not unbearably slow but kiss any dreams of 30 fps goodbye.
I also confirmed that two Thunderbolt Displays worked on the MacBook Pro regardless of the connection configuration.
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repoman27 - Tuesday, September 27, 2011 - link
This is the first display to include ports that have their own host controllers. All other displays either offer just multiple video input ports, or have an internal USB hub and various USB devices that are connected to the USB host controller on a PC via a separate cable. Some also have an audio input as well for a connection to a separate audio output on the PC. So yes, whole different ball game here.I'd rather have a $120k car that doesn't have a stereo or floor mats because they weigh too much. ;-)
I also like displays with height adjustment, but, and not to sound like a total Apple apologist here, Apple generally makes pretty good decisions about which features to include and which to leave out. Whenever you design an electronic gadget you have to make compromises. You can't cram every feature on the market into one device that's smaller and more beautiful than all the others and then sell it for an absurdly low price. The ATD is a pretty balanced package overall. Apple also doesn't have any currently shipping, proven, height-adjustable display stand designs at the moment. If they did, and simply omitted it for this product, it would be far more egregious.
Yeah, stupid consumer HDTV market completely killing the mid-range display market.
AnnonymousCoward - Tuesday, September 27, 2011 - link
The user doesn't care if there's a hub or host directly behind the USB port. It's a friggen USB port, just like my monitor has. And it'd be better if it were USB3, and if there were more than 3 ports. Plug in a mouse and keyboard, and you're quickly left with 1 remaining port, which isn't enough.You don't care to have a stereo in your car? Very odd. I'll take a 15k car with good sound over a silent 120k.
Dell has had their swivel adjustments figured out for several monitor generations. Apple has no excuse, and makes poor feature decisions over and over. Like back when their iPod Shuffle came out, for $90 or whatever and no screen, compared to another brand that cost $35, OLED screen, superior battery life, and functions like a flash drive without iTunes. In addition, Apple's price margins are so high that they can easily afford to add vital features, when competitors have them and sell for less.
repoman27 - Tuesday, September 27, 2011 - link
Of course you don't care how things work, you just buy based on bullet points put forth buy the marketers.How's the throughput on the Gigabit Ethernet port in your display? Does your display have any USB 3.0 ports? Does the PC that it's connected to even have any?
Yeah, and what you consider poor feature decisions have propelled Apple to the #1 ranking market cap in the world. Clearly shareholders are liking the feature set. How's the company that made that other brand doing these days? Dominating the market are they?
AnnonymousCoward - Tuesday, September 27, 2011 - link
Apple is "#1 market cap" because of their marketing department. NOT feature set, nor value.Constructor - Thursday, September 29, 2011 - link
You keep telling yourself that.In the real world, it is actually hard to make the right tradeoffs in product development. And cramming the absolute maximum number of paper features into a product quite often does a disservice to its actual usability and practical usefulness.
Apple's meteoric rise and sky-high user loyalty in large part comes from them in fact making the right decisions in most of these tradeoffs.
"Marketing" is a rather helpless catch-all pseudo-explanation for what many people (and even most competitors) simply fail to grasp. Which is why Apple is successful, and they are not.
AnnonymousCoward - Friday, September 30, 2011 - link
"paper features""disservice to its actual usability and practical usefulness."
-Oh, you mean like a mouse with a right-click button? Yeah, that's quite the paper feature with no practical usefulness!
-Or maybe like putting a screen on an MP3 player. That's yet another worthless paper feature!
-Or a monitor stand with height adjustment. That only looks good on paper! There's no practical usefulness here because every MacHead has a height-adjustable desk!
And don't get me started on the lack of value. You can get a new 15.6" laptop with a C2D-based Intel processor for $280; Apple laptops start at $1000. A while back you could get Apple's 30" (which used an outdated LG panel) for $2000, versus Dell's 30" (with a newer and better LG panel) for $1500, and it had swivel.
I credit the vast majority of Apple's success to their brilliant mass marketing.
crispbp04 - Sunday, September 25, 2011 - link
i just dock my computer and don't have to get flustered over seven cables. snap in and move on. snap off and leave.Constructor - Sunday, September 25, 2011 - link
And all the while there's the massive docking station cluttering up your desk. Which can't be used with any other computer and cannot be adapted to should you need anything it doesn't happen to provide.I'm not saying that it can't be useful, just that Thunderbolt is quite a bit more flexible, more powerful and more convenient.
dsumanik - Tuesday, September 27, 2011 - link
How is that different from a piece of wood or a stack of books for the display to sit on because there is no height adjustment?Constructor - Tuesday, September 27, 2011 - link
You'll need a display in addition to your docking station. The TBD already covers the docking needs, and you can still use the Air's keyboard and trackpad if you like, since there's only one thin cable going out from it, not much different from a USB keyboard cable.And as I explained before: Height adjustment built into the regular stands is usually too limited to be really useful where it's actually needed, and still fragile and wobbly at the same time (which is two things the iMac / Thunderbolt Display stand most certainly is not).
Theoretically demanding all kinds of things is one thing. Ticking them off on a theoretical spec sheet is another.
But the actual, practical reality is usually a completely different thing again. And that is what you have to deal with when you're actually constructing real-life hardware. It's not nearly as simple as is looks from the outside (I'm developing software, hardware and sometimes mechanical components for a living myself).
Bitching is easy. Finding really good solutions for difficult problems is not.