5k iMac crashing. Repeatedly.


macrumors regular
Original poster
Aug 22, 2003
So, I have a 5k iMac. Bought it about 6 months ago. For the past 4 months (at least) it has a habit of crashing. Usually not when I am doing something CPU intensive. It usually seems to happen when the machine is idle. A few times per week. Though it has crashed on me while I was doing something I cared about...

I have a an i7/ 295 with 24GB of RAM (16 from Crucial). 512GB SSD.

Is this common? If I bring it to a genius bar are there any diagnostics they can run on it?

I did do a search on this topic to no avail. And to be clear, this is NOT the well known issue of video stutter. I actually don't haven performance issues per se...




macrumors 6502a
Jan 12, 2004
Had a 2010 that behaved in a similar manner, several years back. I removed the extra RAM (also Crucial), and never had a crash again. I ran it hobbled with less RAM, until I upgraded it. Connected with the buyer, who I'd warned, recently and he said he's still using the system and it never crashed. He had subsequently upgraded the RAM as well. Guess it was just bad sticks?

Not to bag on Crucial, as they are my go-to RAM vendor. But in this case, the stuff was bad.

Weird thing is that the problem didn't manifest itself until a couple months after upgrading the RAM. But it progressively got worse.

take out the crucial ram and see if it happens


macrumors 6502a
Mar 15, 2015
When did you buy those RAM? Could you still return it?

If you want to, find out if it's the RAM, then take out the original RAM and put in crucial. Maybe they don't work together well? That way, if you can't return it, you could use 16GB and keep the original as a backup.


Staff member
May 3, 2009
Yeah. I figured I would have to - but I doubt that is the culprit.
With or with out the memtest, I'd try running the iMac w/o the upgraded ram. If stability returns, then you have your answer.


macrumors regular
Jun 8, 2009
I had issues with my 2014 riMac ( i5/295x Yosemite ), crashing as well. I had upgraded with Crucial memory, thought at first this was the issue, put old RAM back in and still crashing. Many weeks sending apple kernel panic reports ( what a waste of time ). Logic board replacement. A returned scratched up mac, and in the end after many reinstalls, etc I figured out that when I had enabled System Preferences > Accessibility > Reduce transparency ( So the I could use machine with more than a few window open usefully ) it crashed every session. Once turned off, machine lagged but never crashed again. I have not tried El Captain yet, but UI has improved so much ( well at least on my retina 2012 Macbook Pro ) I can't see why it I would need to be enable those options again. Hope this helps.