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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CharonPDX - Friday, September 23, 2011 - link
I had HOPED to buy either a Mac Mini or a MacBook Air this year. Finances aren't allowing that.But, it looks like sometime mid next year, I should be able to upgrade.
At this point, if Anand's wish comes true:
I'll be getting an 11" Ivy Bridge Air and a Thunderbolt Display.
Death666Angel - Friday, September 23, 2011 - link
"capable of at least 350 nits at full brightness"Just wanted to say that Apple actually advertises 375 cd/m² on their website. :-)
tzhu07 - Friday, September 23, 2011 - link
I wish Anand would've addressed the issue of the glossy-only screen option in the video review. Why did Apple and some others continue to seemingly promote this type of screen? There are many people that consider it a deal-breaker, including myself. How much of a hassle is it for Apple to have two variations of the same product?repoman27 - Friday, September 23, 2011 - link
"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."According to Apple's specs, the ATD has a 2.1 speaker system, so it already has a sub of sorts. Also the claimed power for the audio system is 49 watts, which is pretty staggering for something built into a display. Actually it's good compared to most compact PC desktop speaker systems. It's too bad that it impresses more on paper than it would seem to in real life.
dunce - Friday, September 23, 2011 - link
Can I use that Thunderbolt port on the back to plug in a second computer (MacMini/PC)? I am looking at this and the Dell 27in but would like multi computers inputs.Constructor - Saturday, September 24, 2011 - link
No, as far as I'm aware there can only be one master (CPU) on a Thunderbolt chain.kalistan919 - Friday, September 23, 2011 - link
Will Thunderbolt connections be available for the new 28nm gpus that are coming from AMD and Nvidia? Or will Ivy Bridge channel your discrete gpu from the gpu to motherboard to display through a thunderbolt connection on the motherboard? Does anyone know if Apple will come out with a 30" Thunderbolt Display like they did just recently with the 27" display?These are three questions I tried to find but couldn't. Here's another one...would a minidiplayport on the GPU card work with an apple thunderbolt monitor? Anyone have the lowdown on this? Thanks in advance.
ggathagan - Saturday, September 24, 2011 - link
The GPU's themselves do not dictate what type of connection is used; that's up to the video card manufacturer.Remember, however, that Thunderbolt is not a GPU-specific interface, so a discrete video card with a TB connection would require the manufacturer to add the TB controller and its associated circuitry to their video card.
I doubt that'll happen.
Ivy Bridge will not have integrated TB, so the answer to your 2nd question is also "no". The motherboard would have to take the video output, whether from the CPU or from a discrete GPU, and route it through an on-board TB controller.
30" displays are going away in most market sectors, so I doubt you'll see a 30" with Thunderbolt.
More specifically, I doubt you'll see *any* 30" display from Apple in the future.
As to your last question; from the article:
"A Thunderbolt cable can only transmit a Thunderbolt signal. Although DisplayPort is muxed in, if the display on the other end is expecting Thunderbolt and it receives DisplayPort it won't know what to do with it. It's possible Apple could have built in logic to autosense and switch between Thunderbolt and DisplayPort as inputs, but Apple traditionally employs clean breaks rather than long technology transitions. If Apple wants to ensure Thunderbolt gets adopted (at least by its users), this is the way to do it. "
According to this discussion at Apple's site, someone tried using a non-TB MBP and MBA and were not successful.
https://discussions.apple.com/thread/3199231?start...
What I would expect to see is someone marketing a Thunderbolt adaptor that converts a DP input to TB output.
In fact, I would expect to see Apple create this eventually, but it'll be atrociously expensive from them.
Since the whole point of TB is the ability to bundle multiple types of data traffic through a single interface, the only scenario where using a TB-equipped monitor currently make sense is one like this article describes; as an alternative to a docking station for a laptop.
It *would* make sense for a display manufacturer to make a TB-equipped monitor that could auto-sense with the input is DP or TB, but only if you're taking the same approach as Apple and include LAN, USB, audio and FireWire connectivity in the monitor.
If, for instance, Dell were to create a line of TB-equipped monitors with all the connectivity I described above, they could market those monitors in conjunction with a TB-equipped desktop and/or laptop series.
The desktops would only require the TB cable and a power cable; the monitor would handle all the peripheral connections.
Essentially, however, you end up having to decide if you want all your connections at the monitor or at the computer itself.
Historically, people prefer to limit the number of cables hanging off of their monitors and leave the rats nest at the computer.
Where I think TB hold the most promise in relation to desktop systems is in the area of external storage, like the Promise Pegasus Anand mentioned.
Impulses - Saturday, September 24, 2011 - link
Usually I skip video reviews entirely unless it's something that's just not communicable easily in text (factory tours and game trailer for instance)... They just tend to ramble on and/or provide very little info.However, the video on the first page of this review was excellent! You should've started doing these long ago, I actually read the entire review first even tho I'm not even remotely interested in the display (I am curious about Thinderbolt's future tho), and I started front to back as I often do (by reading the conclusion first and then skipping to other interesting parts). Having read the whole thing previous to watching the video I feel like the clip actually did a better job at summing it all up than the conclusion or Final Words, which is very impressive, great job!
ppayne - Saturday, September 24, 2011 - link
I'd love to see mods for this appear. Imagine 2 2.5 inch hard drives wired inside somehow and accessible through Thunderbold?