VGA adapter can't handle 1920x1080@60Hz ?

Question

VGA adapter can't handle 1920x1080@60Hz ?

Hi,

I just found this sub forum so I'm reposting my problem into the proper forum if that's ok.

I bought an Air two days ago with a VGA adaptor, for use with an iiyama 24" VGA monitor.

When I set the monitor to its native 1920x1080@60Hz resolution, I get fast moving zig zag disturbance all over the screen that quickly comes and goes, continuously.

I've tried a different VGA cable and even a different VGA monitor (an HP 2007w). Both monitors have the problem, and only at 1920x1080. When I set either monitor to a lower resolution, the disturbance goes away. Of course I want to be able to use my iiyama's native 1920x1080 resolution.

Any ideas? My guess is that either the SVGA adaptor or the Air's graphics chipset is flawed in terms of driving VGA monitors. I hope I'm wrong.

MacBook Air 11" 1.6 GHz, Mac OS X (10.6.5), 4 GB RAM, 128 GB storage

Posted on Dec 19, 2010 1:37 PM

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Answer 1

ksamel

Level 1

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Dec 19, 2010 6:47 PM in response to Joris Witteman

I have a similar problem with my new MacBook Air 13" w/ 4GB, 256GB SSD, and a 2.13Ghz uP running OSX 10.6.5

My MacBook AIr is attached to a 24" external monitor (same monitor my previous MacBook 13" was attached to) and whenever there is heavy activity on the SSD the video image starts to shimmy, shake and tear. Within seconds of the heavy SSD activity stopping the video returns to normal.

It doesn't matter what the video resolution is set for.

The issue is easily reproduced (on my machine) - start a Time Machine backup, a SuperDuper backup, or any large data transfer.

It's not the monitor as I can attach two computers to the monitor and 'split' the screen. Only the half of the 'split screen' showing the MacBook Air 'shakes' and 'shimmies'. The other half of the 'split screen' is rock solid stable. I've also tried two other monitors... same results.

The MacBook's own screen does not exhibit the problem.

So it's obviously related to the external video path.

Spoke with Apple support and they claim to having never heard of the problem. Yet other folks have reported a similar problem (though not mentioning what triggers the issue) in other support forums.

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Answer 2

ai_

Level 1

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Dec 20, 2010 9:59 AM in response to Joris Witteman

I have observed the same problem. I can easily reproduce the problem by scrolling the screen up and down using the mouse. 1920x1200 and 1600x1200 modes exhibited the problem, but 1680x1050 and 1600x1000 did not for me.

I hope Apple will take this seriously and respond soon.

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Answer 3

Dec 20, 2010 1:51 PM in response to ksamel

I just tried some heavy writing to disk, by doing a cat /dev/random > foo.txt from the Terminal. This didn't trigger any disturbance here, when using a resolution under 1920x1080.

I do very occasionally get the disturbance I described before, for a tenth of a second, on my 1680x1050 HP w2007 monitor. I also get the disturbance, continuously, when I set this HP monitor to 1920x1080 (which it by the way doesn't support, but does try to display downscaled).

I also bought a Mini Display Port to DVI adaptor. I'll see if I can reproduce the disturbance with that. If so, we have a problem that is genuine to the MacBook Air.

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Answer 4

Dec 20, 2010 1:59 PM in response to ai_

Interesting that you get the problem only with resolutions with 1200px height. I only get the problem with 1080px height (and probably over 1080px too).

The problem then seems related to resolutions that are 1080px and up vertically.

Somebody with a 13" MBA however says they're using VGA at 1920x1600 just fine in this thread:
http://discussions.apple.com/thread.jspa?threadID=2680249

If this is true, I'm thinking it's a problem with the 11.6" Air, and that ksamel's problem is a different one.

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Answer 5

Dec 20, 2010 2:09 PM in response to ksamel

ksamel, could you describe what your disturbance looks like when you trigger it with hard drive activity?

I think I was able to reproduce what you mean, by launching iPhoto and loading in a very large library. The dark grey background of iPhoto would slightly flicker.

The disturbances I'm seeing with my 1920x1080 screen however, are zig zag distortions. Are you seeing distortions of any kind? If not, we are talking about different issues.

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Answer 6

ksamel

Level 1

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Dec 20, 2010 4:46 PM in response to Joris Witteman

I'm seeing a zigzag disturbance, with very little if any color or brightness change. Basically all vertical lines start to zigzag left to right.

I have a small video of it that I'd be happy to email to you.

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Answer 7

Dec 20, 2010 5:00 PM in response to ksamel

Thanks ksamel. That's exactly what I'm seeing.

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Answer 8

ai_

Level 1

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Dec 21, 2010 1:48 PM in response to Joris Witteman

Just wanted to add that I am seeing the problem on my 13" MBA.
Also, need to mention that 1680x1050 setting also exhibited similar problem (contrary to my previous posting), though much less frequently and without a clear way to replicate it.

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Answer 9

ksamel

Level 1

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Dec 21, 2010 1:56 PM in response to ai_

Welcome to the club. ;-{

Have you contacted Apple Support ? I'm asking because the more of us that report the issue might help 'convince' Apple we really do need some type of resolution or at least have Apple acknowledge the issue.

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Answer 10

Zwolff

Level 1

14 points

Dec 21, 2010 2:26 PM in response to ai_

Same thing here. My 1680x1050 VGA display connected to my 11'' MBA have the same zigzag distortion every now and then without a clear way to reproduce the problem.

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Answer 11

Zwolff

Level 1

14 points

Dec 22, 2010 7:52 AM in response to ksamel

Just called Apple Support. The guy said that Apple is aware of the MBAs display problems, though he did not specifically said they were aware of the exact same problem as I have.

He suspected that Apple is working on resolving the display problems in the next firmware update and recommended me to wait for the update before sending the computer to repair or anything similar.

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Answer 12

Jan 2, 2011 4:35 AM in response to Zwolff

The support people I've been talking to have also reported the issue to Apple. Apple in turn asked them to ask me to try and install the firmware update at http://support.apple.com/kb/HT3492 , which was two years old and didn't recognize my adaptor or display.

I hope and expect that Apple will offer a solution before too long.

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Answer 13

Jan 5, 2011 3:36 AM in response to Joris Witteman

To all the responders here having this problem, could you please state whether your display is a VGA display, a DVI display or some other display? It would help to make sure this only affects VGA monitors.

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Answer 14

Jan 5, 2011 11:05 AM in response to Joris Witteman

I've tried two different VGA adapters with my MacBook Air 13" on my Sony 520GS in 1600x1200 mode: both show the jittery distortion - though it does see to come and go (haven't seen it for about 5 minutes now). I also used the DVI adapter with my 23" Apple monitor - no problems seen. -jk

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Answer 15

Jan 7, 2011 2:31 AM in response to Joris Witteman

I am somewhat humbled though delighted to report that another Apple MiniDisplay to VGA adapter does not exhibit the problem.

That said, other users in this thread had the problem with multiple ones of the same model.

Both adapters I've tried, the one with and the one without the problem are of the 1.03 firmware. Both show the following info (with relaunches) of the Apple System Profiler:

Adapter Type: Mini DisplayPort To VGA Adapter
Adapter Firmware Version: 1.03

I can say that the one without the problem is significantly older than mine. My girlfriend bought it with her MacBook Pro in March 2010. I will now exchange my problematic one in the Apple store and report back.

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