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To the OP: You're overthinking it. When there is a graphics glitch only during a certain softwarefunction, then it's obviously a software bug - not a bad GPU. Just relax, and wait for Apple to fix the bug.
 
And not everybody has the issue. Just restored some files on my iMac 5K sporting the M295X but didn't get the graphics glitch like the OP did. Bug in Yosemite? Wouldn't surprise me. There are people with a different GPU but the same issue.
 
The fact that not everyone suffers the problem is what is concerning me -'that's why I'm trying to gather photos for a bug report.

I'm going to install Windows on my iMac today and run a couple of games at high settings - push the GPU as much as I can. If there's any slip up, it's going back.
 
The fact that not everyone suffers the problem is what is concerning me -'that's why I'm trying to gather photos for a bug report.

I'm going to install Windows on my iMac today and run a couple of games at high settings - push the GPU as much as I can. If there's any slip up, it's going back.

Better run some benchmarks then. Games wouldn't be as demanding as benchmarks which are designed to push the hardware to the limit.
 
Better run some benchmarks then. Games wouldn't be as demanding as benchmarks which are designed to push the hardware to the limit.


But would I see any graphical glitches with a benchmark? Nothing visual actually happens does it? Never run one before...
 
But would I see any graphical glitches with a benchmark? Nothing visual actually happens does it? Never run one before...

As many of us have said, it's a bug in Yosemite. Feel free to run whatever benchmarks you want - I bet it's just fine.

FYI the second 10.10.2 beta of Yosemite seems to have addressed the issue for me.
 
5K iMac - bad GPU? (M295X)

Yup, getting it over here as well as the occasional distortion on windows in Mission Control. Must be a bug in Yosemite.

Alright that's quite a few people now. I know you've got exactly the same build as me too!

This is looking like a Yosemite issue.

As many of us have said, it's a bug in Yosemite. Feel free to run whatever benchmarks you want - I bet it's just fine.

FYI the second 10.10.2 beta of Yosemite seems to have addressed the issue for me.

I'd like to run a benchmark for my own assurance, really. But thanks for the heads up about 10.10.2 - you're the second person to mention that I think, which is good news.

I realise I'm being over cautious, and that's probably frustrating for you.

I'm pretty sure it would if it's a GPU problem you wouldn't be able to finish a benchmark run otherwise. But I recommend doing Apple Hardware Diagnostics before doing something drastic. Might as well go for it first.

http://support.apple.com/en-us/HT202731

Yep, I ran that yesterday and the iMac passed with 0 issues in only a couple of minutes. Any recommendations for a good GPU benchmark tool?

I'm actually in Kingston, UK as I'm writing this, so I will see if I can replicate the bug on the in-store 5K iMacs.
 
I definitely understand expecting perfection in a machine such as this. I'm currently fretting over noticeable color temperature differences on the display, which actually is a hardware issue.
 
I definitely understand expecting perfection in a machine such as this. I'm currently fretting over noticeable color temperature differences on the display, which actually is a hardware issue.

Exactly.

Since you suffer the TM graphics glitch - any chance you could give this a try? I've just discovered another repeatable glitch in Mission Control, with Activity Monitor.

1. Open up Activity Monitor and leave this Safari window open
2. Swipe/tap into Mission Control, and look in the lower-right corner of the Activity Monitor window
3. Seeing what I and a couple of others are seeing (below)?

This glitch DOES show in screenshots!

r8s2mQI.jpg
 
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Since you suffer the TM graphics glitch - any chance you could give this a try? I've just discovered another repeatable glitch in Mission Control, with Activity Monitor.

As I stated in my earlier comment I have noticed distortion on Mission Control windows as well. For me it becomes most apparent on the Photoshop window.

Someone with a non-retina iMac had started a thread on this issue so it clearly isn't specific to the retina iMac.

Again, wouldn't worry about it. Bugs like this in Yosemite are slowly getting patched.

Any issues on your display? :eek:
 
Exactly.

Since you suffer the TM graphics glitch - any chance you could give this a try? I've just discovered another repeatable glitch in Mission Control, with Activity Monitor.

1. Open up Activity Monitor and leave this Safari window open
2. Swipe/tap into Mission Control, and look in the lower-right corner of the Activity Monitor window
3. Seeing what I and a couple of others are seeing (below)?

This glitch DOES show in screenshots!

Image

I say this politely, but please.. just relax! These are ALL Yosemite issues. Want some more proof? Guess what? I have the same issue as you! And because it seems that nothing less than a screenshot will prove it to you, here's one!

My suggestion: Say, "Thank you WilliamG for putting my mind at ease. It's easy to get obsessive about a computer that cost an arse-ton of money, but I'll let it go and hope that further Yosemite updates fix the remaining glitches."
 

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As I stated in my earlier comment I have noticed distortion on Mission Control windows as well. For me it becomes most apparent on the Photoshop window.



Someone with a non-retina iMac had started a thread on this issue so it clearly isn't specific to the retina iMac.



Again, wouldn't worry about it. Bugs like this in Yosemite are slowly getting patched.



Any issues on your display? :eek:


I haven't tried Photoshop, but I'm assuming we have the same issues.

Not that I could see - no bleed, no dead pixels, whites seem consistent enough for my eyes, and the colours are, well, insane. What exactly are you seeing?

I say this politely, but please.. just relax! These are ALL Yosemite issues. Want some more proof? Guess what? I have the same issue as you! And because it seems that nothing less than a screenshot will prove it to you, here's one!

My suggestion: Say, "Thank you WilliamG for putting my mind at ease. It's easy to get obsessive about a computer that cost an arse-ton of money, but I'll let it go and hope that further Yosemite updates fix the remaining glitches."


Ha, I admit I've become a tad obsessed with this issue. I appreciate your replies, really. It's just a concern when it seems to be a minority of users who suffer the problem, and the initial signs suggest a hardware issue. That 14 day returns window has been a lifesaver for me in the past. I always make the most of it. Regardless, thanks for putting my mind at rest!

I have just managed to get Windows 8.1 installed and run the one game I occasionally play (Americas Army: Proving Grounds Beta). Doing so has definitely helped me relax with the GPU worries.

Within 2 minutes of running the game the fan kicked in at full blast (pretty loud when it gets going, hey?), but the performance jump from my 2010 was suitably impressive. I'm now sitting at 2560x1440 with all maximum graphics settings and getting 50-85 FPS on a notoriously poorly optimised game. Previously I was squeezing 15-50 FPS on minimum settings at 1920x1080.

It can't stand the game at anything near 5K, but we all know that!
 
Have a base 5k and my TM display used to be like that. Never really bothered me as it's a known Yosemite issue. However, just entered TM and the ' split screen ' effect has disappeared. Don't know if this happened after the 10.10.1 upgrade or not though.
 
I get the little artifacts in the corner of Activity Monitor. And I can get it in Path Finder too. Goes away if you move the window a bit. And I sometimes see distortion on windows when using TotalSpaces in all-spaces mode. And DevonThink. You can rid yourself of it if you change the aspect of that Activity Monitor window.

Pause a second and remember what retina is doing: it optimizes the virtual display of your desktop, essentially the picture you see on the screen (virtual screen), depending on the hardware, and it has to access what's called the backing space, and then send that off to be displayed on the hardware itself.

All kinds of things can now go wrong with that, since it isn't as simple as it was before retina. And that's gonna be more apparent when you resize windows as happens with Mission Control. Try opening Activity Monitor in low resolution mode, for example; it will look like a dog's breakfast but at least those artifacts disappear when you go all Mission Control on it.

As time goes by applications, websites, and such will become more retina friendly, and this stuff will be cleaned up. It's not trivial and it's amazing it works as well as it does right now.
 
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