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
Trouble in Promise-land
What's the first thing you do when you've got a display that has tons of interfaces and bandwidth at its disposal? Try them all at once to see if anything breaks of course. Over the course of the past few days that's exactly what I did. Unfortunately I did find a situation where things broke.
For whatever reason, if you're doing a lot of writes to the Promise Pegasus while playing music (or any other constant audio) through the Thunderbolt Display's internal speakers the audio will eventually corrupt. You can hear exactly what I'm talking about below:
TB Pegasus Audio Issue by AnandTech
This is a recording taken of me listening to music on the Thunderbolt Display (via its internal speakers) while writing a couple hundred gigabytes to the Pegasus R6. Note the introduction of what can only be described as really bad noise at the 6 second marker.
If you stop music playback and quickly resume, the problem will still be there. You have to restart the application that's using the audio codec to recover from this point. From a hardware standpoint, the codec just needs to go through an off/on (sleep/wake?) cycle to return back to normal. If you do this however and haven't stopped the transfer, the problem will creep up again. Stopping the transfer while playing back music won't fix the issue either. You have to stop the transfer and restart the music playback application for it to go away.
The issue goes deeper than that. I went out and bought a Creative Labs X-Fi Go Pro USB sound card to see if the problem stopped at the internal audio codec or extended to all USB sound devices. Unfortunately, it does even happen if you're using an external USB sound card connected to the Thunderbolt Display. Connect the same sound card directly to your Mac or use your Mac's 1/8" stereo jack and the problem goes away.
I was worried that what may appear as noise through speakers could result in data corruption over USB transfers. I ran the Pegasus write test while copying a bunch of files to an SSD attached via USB to the Thunderbolt Display and never saw any corruption on the SSD. This appears to be limited entirely to audio playback.
What's truly bizarre is I can only get the issue to appear when writing to the Pegasus, hundreds of GBs of sequential reads don't seem to produce it. Short bursts of writes don't seem to cause it either. Sending tons of data across the monitor's Gigabit Ethernet, FireWire 800 and USB ports doesn't seem to trigger it either. It appears to be an issue with the Pegasus and the Thunderbolt Display. But which device is ultimately at fault? Is it a problem with the Thunderbolt Display or the Pegasus? Ideally I'd use another Thunderbolt storage device to see if the issue remained, but I couldn't get my hands on a LaCie Little Big Disk.
I thought of something else.
First I needed to test and see if perhaps the issue was related to ultra high speed transfers. As we've already shown, the Pegasus can push as much as 1GB/s over Thunderbolt whereas none of the other bandwidth eaters come even remotely close to that. To determine if the issue was data rate invariant I wrote to the Pegasus at different speeds ranging from 480Mbps all the way up to 7.2Gbps. I tried putting SSDs in the Pegasus as well as standard mechanical hard drives. The problem remained. I got audio corruption regardless of what drives were in the Pegasus or what speed I wrote to the drives. The problem wasn't related to transfer rates.
I also took apart the Thunderbolt Display to confirm there weren't any obvious issues on the controller board (E.g. putting the Thunderbolt IC far too close to the audio controller). Nothing obvious there either.
While I was doing all of this, Apple put forth a Thunderbolt firmware update the other day, however it didn't seem to address the issue either. So I went back to my testing.
Since the problem appeared regardless of how fast (or slow) I was transferring and all I needed was another Thunderbolt storage device to vindicate either the Pegasus or the Thunderbolt Display I turned to the trusty MacBook Air.
As I mentioned in our original Pegasus review, if you have two Thunderbolt equipped Macs and a Thunderbolt cable you can actually put one of the machines in target disk mode and access its drives via Thunderbolt on the remaining Mac. You don't get super high performance but you can get around 500Mbps. Since I had reproduced the audio corruption issue at an even slower data rate I decided to give this a try.
I booted the MacBook Air in target disk mode by holding down the 't' key after turning on the machine. My MacBook Pro was connected to the Apple Thunderbolt Display and a Thunderbolt cable connected the display to the MacBook Air. This was the same setup as the Pegasus, but with the MBA in place of the Pegasus.
I wrote to the MBA just like I did the Pegasus (from a file server connected over the Thunderbolt Display's GigE, transfer rates were capped at around 500Mbps from the file server). After a couple hundred gigabytes were transferred without any audio corruption I swapped out the MBA and connected the Pegasus. I copied the same files at the same rate from the same source. After no more than 7GBs were written to the Pegasus the audio stream started to corrupt.
Based on my testing I can only conclude that the Pegasus seems to be at fault here, not the Thunderbolt Display. Given that the Pegasus was introduced prior to Apple's Thunderbolt Display it's not all that surprising that this issue made it through to production. It's unclear what the root cause is but it's hopefully something Promise can address either through firmware or a driver revision.
Update: I'm still verifying that this is indeed a "fix" but it looks like if you use a USB sound card plugged into a USB hub which is then plugged into the Thunderbolt Display then the sound corruption doesn't happen. This seems to point at noisy power as being the cause with the USB hub acting as a crude filter. It's still not ideal but this may be a workaround for Pegasus users until Promise supplies a fix.
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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.