New 27" Thunderbolt Display Flickers when attached to new 27" iMac

I put in a support ticket and ended up dealing with a nice fellow high up in the ranks with the LED dev team. He shipped me a new 27" TB display but the flickering still persists. Also taking into account other people's experience, I think it's almost definitely proven that it's a software or hardware incompatibility in general, and not particular displays failing.

I'm still dealing with the flickering issue after applying all the firmware updates and after getting a replacement.

I've been very patient but it's starting to get a little frustating.

So far I was not able to relate this issue to a specific software since it always happens in a different situation (using the email app, iTunes, Xcode, Safari).

I agree. This is grating on the nerves more than just a bit.

This is what blows my mind - how many Macs are there that even have Thunderbolt? We're not talking about engineering a display to have to work with umpteen billion PCs and their melting pot of hardware. There's probably less Macs than I can count on one hand that would have to be employed in testing the compatibility of this product, and they still f*** it up. Mind boggling.

I do believe that the MEMORY upgrade may have something to do with this. I have been really feeling lucky becasue of all of the COMPLAINTS about the thunderbolt display. I have a 2011 mac mini server that I ordered from APPLE day one with 8 MB ram factory installed. When I ordered my THUNDERBOLT i did not have the flicker issue. I did have the issue of it going to sleep and not waing but that was fixed by turning off the auto brightness adjustment.

I have had no problems since then and have had the Thunderbolt since it first came out. I have installed OWC 16 GB samsung kit and now my monitor is having the FLICKERING issue. I am going to take out the memory and go back to the factory installed 8 and see if that fixes it..... IF it does back with the 16GB samsung from OWC. Anyone having the flickering with other 16GB kits. I went for the more expensive OWC kit becaust I thought I would be better off than with CRUCIAL or Patriot. Anyone else upgrading having issues with another kit?

I also have 16GB installed on my iMac so we may be onto something here, tomorrow I will call the senior advisor that is working on my case and I will send her a link to this discussion so she can see that having 16GB seems to be a common factor here.

Like I posted earlier in this thread, I put in 8GB memory and no flickering. When I put 16GB in, the flickering started for the first time. Both RAM upgrades were OWC.

Yesterday I got my thunderbolt display back from repair...brought it as the USB hub wasn't visible anymore..so no brightness adjustments, no camera, sound and external USB devices were seen..

But when I attached it to my iMac with 16GB RAM still no USB to be seen..so I thought I give it a try and removed 8GB RAM...and voilà...USB is also working again with 8GB RAM on my iMac27...

This is really weired...how can the amount of system RAM influence flickering and USB hub removal?

The support guy yesterday suggested me I call agin this morning and ask for a 2nd level technical assistant...

I just wanted to report back some information to the group. I have put back in my original 8 GB factory installed ram and I have no flickering. I did recieve a call from a TECH on the 23rd that was responding to the info that I had left here and he also asked me to put back in the original memory and see what happens. I will report the info back to him as well so that he can know that there seems to be an issue still with people that have higher than 8GB in their machines or something along those lines. Im trying to decide if I should send back my memory upgrade to OWC. I really can not use it with the FLICKER it is WAY too annoying. And the more memory I seemed to use with more applications running the worse it would get. Righ now Im using 7GB if the 8 and no problems but when I was using 9 GB of the 16 it was flickering A LOT. And more than when I was using 6.5 of 16. So we will see what they come up with.

In the meantime I think Ill send back my memory upgrade. No use in spending that kind of money to let it sit.

Have you tried 12GB? As in, 4GB+8GB or 8GB+4GB? I'm just wondering of it's reacting to 16GB total, or reacting to the fact there is at least one 8GB stick in? And then, which slot causes issues if applicable?

I would hate to give up 16GB total to revert to 8GB total, but 12GB total would be a better compromise in the meantime until (if ever) Apple can sort this mess out.

I am running right now with 4GB+8GB and am having no issues with flickering. I have not tried the other 8GB stick yet with a 4 but will try that shortly. I have a 4GB in the slot closest to the mother board and an 8GB in the slot closest to where you take the top off. Im using 7 GB of 12 right now and no issues.

I spoke a little too soon - It does still flicker with the 12 GB it just does it a lot less. It takes a while between times. I can stand it at this level because it is so long in between times Im at 8.5 out of 12 right now and it does it about every 15 min now. It was doing it about every minute before.

Well it has only done it twice in a couple of hours.

I noticed when iTunes has its visualizer (Apple+T) in full screen (Apple+F) the flickering goes nuts - at least one flicker every 10 seconds, but often more frequent than that. In my experience it is seeming more and more that any video or GPU intensive activity makes the flickering worse.

I've done a few of my own experiments using the full-screen iTunes visualizer and swapping RAM around: I have 2 identical 2011 Mac Mini servers (A and B).

Test 1: Mini A, 16GB RAM: flickers like crazy, and has flickered ever since I got the TB display. In fact, I had the TB display go black and not come back at least once - had to unplug the display to revive it.

Test 2: Mini B, 8GB RAM: no flickers (preliminarily - only tested for ~10 minutes)

Test 3: Mini B, 16GB RAM: no flickers (preliminarily - only tested for ~10 minutes)

Test 4: Mini A, 8GB RAM: no flickers

Not sure what to make of this. I've had the visualizer running for hours in the Test 4 configuration and have not seen any flickers with my eyes. The reason why I only tested Test 2 and Test 3 for 10 minutes is that, with Test 1, the flickers would start within minutes of throwing the visualizer up.