Graphic anomalies on iMac Retina 5K on scaled resolutions for more space.

Question

Graphic anomalies on iMac Retina 5K on scaled resolutions for more space.

Is anyone else getting graphic anomalies when using a scaled resolution higher than default? I get them when I drag windows and they look like this:

It does not seem to happen if I keep the resolution at "default for display" or scaled, but default or lower. This is on the latest hardware update to the iMac (Retina 5K, 27-inch, Late 2014) running 10.10.3 with all other updates installed. Just received the computer on Friday and it did this out of the box...

Mac (Retina 5K, 27-inch, Late 2014)

4 GHz Intel Core i7

16 GB 1600 MHz DDR3

AMD Radeon R9 M295X 4096 MB

Posted on Jun 1, 2015 8:56 AM

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Answer 1

Jun 1, 2015 8:59 AM in response to Dan Wilkerson

Small update, it does the same graphic garbled mess under any other scaled option other than default.

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Answer 2

Linc Davis

Level 10

209,739 points

Jun 1, 2015 10:33 AM in response to Dan Wilkerson

The warranty entitles you to complimentary phone support for the first 90 days of ownership.

If you bought the product in the U.S. directly from Apple (not from a reseller), you have 14 days from the date of delivery in which to exchange or return it for a refund. In other countries, the return policy may be different. If you bought from a reseller, its return policy applies.

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Answer 3

Jun 3, 2015 2:28 PM in response to Dan Wilkerson

TLDR; the problem was from an EFI boot loader that I had installed.

Took this to the genius bar yesterday. We ended up doing a fresh install, got rid of my Windows partition and installed back on a clean install of Yosemite. The problem went away. So I took my computer back home and started reinstalling everything. I installed rEFInd (a custom EFI boot loader I use on my other machines) and the problem came back. Uninstalled and reinstalled a few times to be sure and it is the culprit.

One of the big benefits of the boot loader (at least to me) was to not have to hold the option(alt) key on startup. It would automatically allow me to pick which partition to boot from on each and every boot up. Now if I instead held the option key (as you would without the boot loader installed) and manually picked the startup drive this would also "fix" the graphics issue I had without having to uninstall the boot loader. However I ended up removing rEFInd (or rEFIt, I tried both) completely anyway and the issue is gone.

I have a 512GB SSD on this computer and saw that there are some possible issues for drives over 500GB, but for hard drive corruption. If I had to guess the combination of the SSD and the boot loader is the cause of the graphics issue. (as odd as that sounds).

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