Greetings Hackintosh enthusiasts,
I'm a proud owner of i7-4770K & GA-z87x-u5dh build and have (same as most of you) battled with system instability in the form of constant freezes while trying to make the Hack work with 4x8GB of RAM. I'm writing this post as my own tribute to this issue and hope you'll have some use of my experience in making your Hacks behave like they should
The build
My system is running Mavericks 10.9.2 which was a clean install (latest Mavericks version from AppStore at the time) on mentioned CPU&MBO combo accompanied by GeForce GTX 770 4GB (Gainward Phantom II),
4x8GB Kingston HyperX Blu 1600 MHz RAM and Samsung 840 PRO 256GB SDD. Important info to mention is that my RAM is
not marked as Intel XMP-compliant and was not a part of some memory KIT - each stick was sold individually - you can find exact specs
here. My MBO was flashed to the latest BIOS version - F9.
The issue
OSX install & post-install (Multibeast) was done 'by-the-book' and went without issues.
Later on I started experiencing system freezes (image was on the screen but everything else was dead) mostly under little load - e.g. during web browsing, youtube watching, etc. They would occur randomly from like 2 seconds of uptime to 12 hours of uptime - obviously no rule here and clearly not related to system load/temperatures/whatever.
Diagnosis
As I stated earlier this issue is not related to system load nor temperatures so could it be caused by the OS? Definitely NOT. How am I so sure, you ask? At one (lucky?) moment my
system froze while I was in BIOS and that gave it away. Such freezes are 99% of times related to faulty/wrongly-configured RAM.
The hope
I decided to load fail-safe BIOS options and start my machine with default memory settings (
1333MHz, latencies at 9-9-9-24 & voltage set to 1.5V). I've tested the system using Prime95's 'Torture' test and it finished with flying colors while showing zero errors! At that point I knew my RAM is not faulty but 'temperamental' and only needs to be 'tuned-up' properly to work at factory-declared speeds (1600MHz) as it clearly needed more 'juice' to provide my goal frequency.
The solution
Once again I've bumped-up RAM to 1600 MHz by setting up it's multiplier to 16 with
XMP turned off BUT this time I've set up latencies
manually to 10-10-10-27 (which was declared by the manufacturer for 1600MHz) AND
bumped-up RAM voltage to 1.55V - that's
+0.5 from what manufactured stated to be enough to operate at this frequency. Last but not the least you should completely
TURN OFF the machine after BIOS save and give it a 30 seconds rest before switching it back on (I have initially only restarted and RAM settings remained unchanged!!!).
The confirmation
Once again I fired-up Prime95 & initiated Torture test (which particularly stresses the RAM) while having opened 10 youtube videos (lasting for 100 hours - e.g. Nyan cat
) in multiple browsers, running RAR compression on 200GB of images and playing 2 BlueRay videos at the same time. All of that skyrocketed CPU usage to 100% and it's temperatures reached almost 100 Degs. After 4 hours of this torture everything was still running without a glitch and at that point I decided to open a beer
Feeling nicely refreshed and optimistic I went to sleep. Next morning the tests were still running and the system was operating flawlessly. That continued for another few hours and finally when the test was finished it results showed no errors. My system was finally cured! Weeeeeee
A week passed since then and I had no freeze occurrences yet.
The summary
From my experience this issue is caused by specific combination of Z87 chipset and 4 DIMMs of RAM. Specifically it looks like Z87's memory controller is simply not able to handle all that memory. In order to run the system with 4 DIMMs you'll need to
MANUALLY set memory speed and latencies to manufacturer declared values,
bump memory voltage by +0.5V and
disable XMP. Leave all other BIOS options at fail-safe settings. If you still don't achieve system stability then try to raise memory voltage by additional +0.5V but don't go higher than that. If the issue persists then most probably you are a victim of a faulty memory stick(s).
Hope this helps someone as many of this Forum's posts have helped me in the past
Good bye & good luck!