1.35 V & 1.5 V RAM for late 2013 iMac's

[SaSaSushi]

I removed the stock modules and installed 4 corsair modules.

Thanks, good to know.

Others have reported success in adding 2x8GB to the Apple stock RAM for 32GB though.

In the meantime, I still can't get this stupid thing to panic now that I've reseated and reversed the DIMMs. It would be so much easier to diagnose if there was something that could reliably trigger the crashes.

If it keeps running until tomorrow morning without any problems, I'll have a big decision to make on the RMA.

 

[minimalism]

Can anyone confirm if SAMSUNG 8GB 204 pin DDR3L-1600 SO-DIMM (1600Mhz, PC3L-12800S, CL11, 1.35V Low Power) works for late-2013 iMac at max of 32GB?

 

[SaSaSushi]

Can anyone confirm if SAMSUNG 8GB 204 pin DDR3L-1600 SO-DIMM (1600Mhz, PC3L-12800S, CL11, 1.35V Low Power) works for late-2013 iMac at max of 32GB?

The Team Elite DDR3L I was testing finally panicked my machine so I returned it and now, as a final effort, I bit the bullet and ordered the Crucial CT2K8G3S160BM DDR3L from Amazon US.

I am beginning to think that this is not a hardware issue, but Apple's problem and I will be convinced if this Crucial RAM exhibits the same system instabilities. At that point, I will be opening a case with AppleCare.

Hopefully, the Crucial will work though and it won't come to that.

 

[minimalism]

The Team Elite DDR3L I was testing finally panicked my machine so I returned it and now, as a final effort, I bit the bullet and ordered the Crucial CT2K8G3S160BM DDR3L from Amazon US.

I am beginning to think that this is not a hardware issue, but Apple's problem and I will be convinced if this Crucial RAM exhibits the same system instabilities. At that point, I will be opening a case with AppleCare.

Hopefully, the Crucial will work though and it won't come to that.

Fingers crossed mate. Update us!

 

[SaSaSushi]

Fingers crossed mate. Update us!

Thank you very much!

It should arrive in a day or two and I will definitely post the results.

All I'm looking for is for the machine to run as rock stably with 32GB as it does with 16GB. The really frustrating thing was that it didn't seem to matter whether I had just the third party RAM or the Apple stock Elpida RAM installed, the machine seemed fine at 16GB. The problems were all with the full 32GB.

Besides the fact that Crucial markets and sells their RAM as fully Haswell Mac-compatible, from SPD data I've seen posted online, it seems to be nearly identical in specs to the Apple RAM down to almost every parameter. We'll see...

As I mentioned in a similar thread on Apple's forums, Crucial is just the brand name that Micron sells its consumer products under. Elpida is a Japanese company that went bankrupt in 2012 and was then acquired by Micron. In other words, Elpida is Micron (Crucial) now. They are currently continuing to manufacture some products (including the RAM that Apple ships many Macs with) under the Elpida name, but that will change within a year or two.

 

[nottoohigh]

I just registered as I've been following this thread while researching what ram to get to upgrade my new late 2013 27" imac. It came with stock 8gb which are labelled hynix 12800 PC3L. Doesn't say voltage but I guess from what others say should be 1.35v.

Thought I'd share my experience in case it helps anyone else.

Anyway i opted to get crucial CT102464BF160B
8GB DDR3L-1600 SODIMM ( DDR3L 1.35V ) as a local shop where I live had that in stock. I'm outside the US. Got 2 sticks for 16gb. Added these on top of the 2 sticks of 4gb stock apple supplied Hynix for total of 24gbs. So 4 slots filled but not maxed to 32gb as some people are asking about. Been running a day now without issue. My home grown stress test so far has been running handbrake on a 3.2gb avi, while playing 2 videos one in QuickTime and one in vlc, while encoding 3gbs of videos via ffmpeg on command line while watching one YouTube video and doing a bunch of image editing in Photoshop at the same time. No issues so far. Fingers crossed this will be stable for me.

 

[minimalism]

I just registered as I've been following this thread while researching what ram to get to upgrade my new late 2013 27" imac. It came with stock 8gb which are labelled hynix 12800 PC3L. Doesn't say voltage but I guess from what others say should be 1.35v.

Thought I'd share my experience in case it helps anyone else.

Anyway i opted to get crucial CT102464BF160B
8GB DDR3L-1600 SODIMM ( DDR3L 1.35V ) as a local shop where I live had that in stock. I'm outside the US. Got 2 sticks for 16gb. Added these on top of the 2 sticks of 4gb stock apple supplied Hynix for total of 24gbs. So 4 slots filled but not maxed to 32gb as some people are asking about. Been running a day now without issue. My home grown stress test so far has been running handbrake on a 3.2gb avi, while playing 2 videos one in QuickTime and one in vlc, while encoding 3gbs of videos via ffmpeg on command line while watching one YouTube video and doing a bunch of image editing in Photoshop at the same time. No issues so far. Fingers crossed this will be stable for me.

Thanks for sharing your experience! Based on other people's experiences, only when you max it at 32GB that the crashing manifests itself.

 

[Sukka90]

I've too been following this thread for some time now in order to determine what would be the best 32GB RAM for my new 27" iMac.

Got a pretty good deal for 2x 2x8GB Kingston HyperX LoVo DDR3L 1.35v 1600MHz CL9 KHX16LS9P1K2/16 (The same kit that IA64 earlier reported to be working).

Decided to get these, not just because of their price, which was actually cheaper than Corsair's Mac-specific CL11 kit, but also because they're faster and that the CL9 latency is in the JEDEC configuration and don't have to be set manually or via XMP, which I don't think Macs have support for (correct me if I'm wrong).

Anyways, I've been running these for about 24 hours now without any issues, speed and the latency also seems to be reporting fine.

Just thought to let all you guys know, in case there's more people wondering what RAM to get for 32GB.

Picture of the original 2x4GB memory the iMac came with
Kingston memory

 

[SaSaSushi]

Got my Crucial RAM from Amazon US last night. I installed it this morning and I will follow up with my results, good or bad.

For those interested. The model number on these DIMMS is

CT8G3S160BM.C16FER

Micron's part number is MT16KTF1G64HZ-1G6E1

It's probably just my imagination and I'm sure to jinx myself by saying so, but things do seem snappier with this RAM than the ones I tried before.

Anyway, as I may have mentioned before, I'm done replacing RAM. It's three strikes and you're out for Apple. If the kernel panics/freezing/spontaneous shutdowns continue with this RAM I am taking it up with AppleCare.

This is the third brand of quality RAM I've installed and this last one is marketed specifically for these new Macs. No computer should be that sensitive with upgrade RAM.

 

[LosingThe Plot]

RipJaws also create Panics with 32GB

Got the 16GB of G.Skill memory installed today. This gives me an approx 5% boost over 8GB of the Apple Memory. The momory shows up as 1867 in System Info.

Hi ender78

I am about to return the Ripjaws

http://www.memoryc.co.uk/products/d...emory_dual_channel_kit-2x_8GB-CL10/index.html

I am getting panics and reboots with all 4 slots used 4 8Gb sticks
stock Apple Memory in runs fine

This memory appears not to be comparable, all that was running was Safari so no great load on the CPU or RAM

Anyone have a 32Gb upgrade that is working?

iMAC 27"
Late 2013
8GB RAM
3.4 Ghz i5
Graphics NVIDIA GeForce GTX 780M 4096 MB

 

[SaSaSushi]

Anyone have a 32Gb upgrade that is working?

I do.... finally.

The 16GB of Crucial RAM mentioned above (http://amzn.to/MqBZPR) has been running on my system along with the 16GB of stock Apple RAM for just shy of a week now 100% issue-free.

I went through two other brands before this, CFD 1.5 V and Team Elite 1.35 V and neither of those could go one full day without kernel panics, freezing or spontaneous reboots. Therefore, I now consider this issue, thankfully, resolved.

 

[unfragile]

I do.... finally.

The 16GB of Crucial RAM mentioned above (http://amzn.to/MqBZPR) has been running on my system along with the 16GB of stock Apple RAM for just shy of a week now 100% issue-free.

I went through two other brands before this, CFD 1.5 V and Team Elite 1.35 V and neither of those could go one full day without kernel panics, freezing or spontaneous reboots. Therefore, I now consider this issue, thankfully, resolved.

Im happy that you find a memory that workd.


I've return my iMac. I cant spend 2500€ in a machine and then spend more time looking for 3rd party ram.

Waiting for my nMac Pro 6core/D500/512gb/12gb upgrade to 32gb ram (crucial).

Cheers

 

[SaSaSushi]

Im happy that you find a memory that workd.

Thanks, if this Crucial RAM hadn't worked, I was getting ready to send my iMac back to Apple myself.

I've return my iMac. I cant spend 2500€ in a machine and then spend more time looking for 3rd party ram.

I don't blame you a bit. It is a ridiculous hassle and this is the first Mac I've ever experienced such sensitivities with.

Waiting for my nMac Pro 6core/D500/512gb/12gb upgrade to 32gb ram (crucial).

Nice. Enjoy it.

 

[LosingThe Plot]

I do.... finally.

The 16GB of Crucial RAM mentioned above (http://amzn.to/MqBZPR) has been running on my system along with the 16GB of stock Apple RAM for just shy of a week now 100% issue-free.

)

SaSaSushi

Thank you,

this shouldn't be so hard to do

 

[jomanlo]

I come back to give you a small update after 2 weeks of use with 32Gb inside.

No panics/errors/freeze with installed memory:

CORSAIR Vengeance
CMSX16GX3M2A1600C10
4x 8GB, DDR3-SODIMM, PC3-12800 (1600MHz), CL10, 1,5V

Maybe it is due to my use (ms office, mail, skype, safari, chrome) but I do not have problems.

I almost always have Safari/Chrome open, half screen each, playing flash games, with other applications open and nothing to report.

It seems very difficult to find a reason why some 27 Imac Late 2013 crash...

However I agree and confirm that the increase of ram was not useful for my needs, maybe for the future.

 

[ender78]

Hi ender78

I am about to return the Ripjaws

http://www.memoryc.co.uk/products/d...emory_dual_channel_kit-2x_8GB-CL10/index.html

I am getting panics and reboots with all 4 slots used 4 8Gb sticks
stock Apple Memory in runs fine

This memory appears not to be comparable, all that was running was Safari so no great load on the CPU or RAM

Anyone have a 32Gb upgrade that is working?

iMAC 27"
Late 2013
8GB RAM
3.4 Ghz i5
Graphics NVIDIA GeForce GTX 780M 4096 MB

I am only at 16GB and have never seen a Kernel panic. Could just be some bad memory and not a compatibility problem.

 

[SaSaSushi]

I am only at 16GB and have never seen a Kernel panic. Could just be some bad memory and not a compatibility problem.

It could be, but I never had problems at only 16GB either. Even with the RAM I ended up returning installed on its own the panics stopped. The problems only started when there was 32GB installed.

I don't think I've seen any accounts yet of instability with only 16GB.

 

[Chippy99]

I come back to give you a small update after 2 weeks of use with 32Gb inside.

No panics/errors/freeze with installed memory:

CORSAIR Vengeance
CMSX16GX3M2A1600C10
4x 8GB, DDR3-SODIMM, PC3-12800 (1600MHz), CL10, 1,5V
...
Imac 27 Late 2013, i5 3.2Ghz, 32Gb Ram, 256Gb SSD

Did you read this, IA64?

 

[SaSaSushi]

I come back to give you a small update after 2 weeks of use with 32Gb inside.

No panics/errors/freeze with installed memory:

CORSAIR Vengeance
CMSX16GX3M2A1600C10
4x 8GB, DDR3-SODIMM, PC3-12800 (1600MHz), CL10, 1,5V

I am very happy to hear about your success and hope that your problems are solved for good.

However, I have a sadder story of my own to report.

After more than two weeks of absolutely no issues whatsoever with my new Crucial RAM I had a kernel panic. Then within 24 hours another panic followed that contained the following ominous lines in the log:

panic(cpu 6 caller 0xffffff800f4c4516): "Possible memory corruption: pmap_pv_remove(0xffffff80520d8e78, 0x12222b000, 0x2d660, 0x1c00002d660066, 0xffffff83b6dc3bb4, 0xffffff83b6dc3ba8): pv not on hash, head: 0xffffff80520d8e78, 0x1363a3000"@/SourceCache/xnu/xnu-2422.90.20/osfmk/i386/pmap_internal.h:836
Backtrace (CPU 6), Frame : Return Address
0xffffff83b6dc39f0 : 0xffffff800f422fa9
0xffffff83b6dc3a70 : 0xffffff800f4c4516
0xffffff83b6dc3be0 : 0xffffff800f477587
0xffffff83b6dc3d50 : 0xffffff800f478fdf
0xffffff83b6dc3f20 : 0xffffff800f4dc26c
0xffffff83b6dc3fb0 : 0xffffff800f4f322b

As is widely reported in here, the kernel panics with problem RAM are totally random and impossible to induce. However, I created a Memtest86 EFI boot CD and booted to it. Usually when I run Memtest86 I get no errors on any of the RAM I've tried but have always just run it in the default single-CPU mode. This time I set it to multi-CPU Parallel mode.

I realized that not only does it run the tests much quicker (duh), I was seeing errors in a lot of the tests. So I removed the Crucial DIMMs and ran the test on just the Apple Elpida 2x8GB and went through an entire pass error-free. Just to make sure, i removed the Apple RAM and put in only the Crucial by itself and ran the test and the same errors were back.

So I have a replacement set on the way from Amazon, but the good news is I no longer have to wait for random kernel panics since a Memtest86 test in multi-CPU mode will be the first item on the agenda.

I urge anyone else having problems with their RAM to try Memtest86 in multi-CPU Parallel mode (http://www.memtest86.com/download.htm)

 

[LosingThe Plot]

I am very happy to hear about your success and hope that your problems are solved for good.

However, I have a sadder story of my own to report.

After more than two weeks of absolutely no issues whatsoever with my new Crucial RAM I had a kernel panic. Then within 24 hours another panic followed that contained the following ominous lines in the log:

panic(cpu 6 caller 0xffffff800f4c4516): "Possible memory corruption: pmap_pv_remove(0xffffff80520d8e78, 0x12222b000, 0x2d660, 0x1c00002d660066, 0xffffff83b6dc3bb4, 0xffffff83b6dc3ba8): pv not on hash, head: 0xffffff80520d8e78, 0x1363a3000"@/SourceCache/xnu/xnu-2422.90.20/osfmk/i386/pmap_internal.h:836
Backtrace (CPU 6), Frame : Return Address
0xffffff83b6dc39f0 : 0xffffff800f422fa9
0xffffff83b6dc3a70 : 0xffffff800f4c4516
0xffffff83b6dc3be0 : 0xffffff800f477587
0xffffff83b6dc3d50 : 0xffffff800f478fdf
0xffffff83b6dc3f20 : 0xffffff800f4dc26c
0xffffff83b6dc3fb0 : 0xffffff800f4f322b

As is widely reported in here, the kernel panics with problem RAM are totally random and impossible to induce. However, I created a Memtest86 EFI boot CD and booted to it. Usually when I run Memtest86 I get no errors on any of the RAM I've tried but have always just run it in the default single-CPU mode. This time I set it to multi-CPU Parallel mode.

I realized that not only does it run the tests much quicker (duh), I was seeing errors in a lot of the tests. So I removed the Crucial DIMMs and ran the test on just the Apple Elpida 2x8GB and went through an entire pass error-free. Just to make sure, i removed the Apple RAM and put in only the Crucial by itself and ran the test and the same errors were back.

So I have a replacement set on the way from Amazon, but the good news is I no longer have to wait for random kernel panics since a Memtest86 test in multi-CPU mode will be the first item on the agenda.

I urge anyone else having problems with their RAM to try Memtest86 in multi-CPU Parallel mode (http://www.memtest86.com/download.htm)

This makes me want to hold off purchasing the Crucial Memory

this is the recommended RAM from Crucial

16GB kit (8GBx2), 204-pin SODIMM, DDR3 PC3-12800 memory module

Part Number: CT4951620
Module Size: 16GB kit (8GBx2)
Package: 204-pin SODIMM
Feature: DDR3 PC3-12800
Specs: DDR3 PC3-12800 • CL=11 • Unbuffered • NON-ECC • DDR3-1600 • 1.35V • 1024Meg x 64 • lead free • halogen free • for Mac

Since removing the Rip Jaws and installing the original Apple RAM I haven't had a panic event

 

[SaSaSushi]

This makes me want to hold off purchasing the Crucial Memory

Well I should have my Crucial replacement within a day or two and I will post my results. I'm hoping it was just a bad stick. It is bizarre that I had not the slightest problem in the first two weeks or so of use and then *boom*, kernel panics.

Then again, in a similar thread I am following on the Apple discussion forums, some users with Kingston RAM are reporting the same kernel panics, yet they show no errors in Memtest86.

The problem may turn out to be on the iMac for some users experiencing these problems. The user mentioned wrote:

"My ASP told me that the RAM sensitivity of Haswell iMacs seems to be due to a wrong power supply calibration of RAM modules that are declared as working at 1.35V, athough this is not their effective working voltage (this is the case of Kingstons').
I think that a firmware update addressed to a recalibration of the mac's SMC could solve the problem..."

Since removing the Rip Jaws and installing the original Apple RAM I haven't had a panic event

I'm back on the original Apple 16GB whilst I wait for the new replacement RAM and I've never once had any problems with it. However, I did experience some lockups due to a separate USB3 issue back when I was using 10.9.1.

 

[sahni130]

Did I upgrade right?

Guys, I added 16GB of memory to the stock 8GB that was already in my iMac. I left the stock memory in their original slots and put the new crucial memory in the slots that were empty. Am i running in "matched pairs"?

 

[SaSaSushi]

I just took delivery of my replacement Crucial RAM from Amazon and a few things give me reason for cautious optimism.

1) I immediately installed the two Crucial DIMMs on their own and ran Memtest86 in multi-CPU Parallel Mode and went through two passes with no errors. The ones I returned couldn't get through one pass without throwing errors.

2) Checking the SPD data with TechTool Pro I have confirmed that the specs of these new modules are identical down to every last value. This, too, was not the case with the Crucial I returned. It was almost identical, but some of the timings differed. In particular, tRFC (whatever that is) was 300 on the previous Crucial and is now 260, the same as the Apple Elpida. There was one other different value, but I can't recall it offhand.

3) There was no 20-30 second delay on initial boot up with the new RAM installed. This may mean nothing, but I had it every other time I installed new modules, so I mention it.

So now comes the true test. I will report back in a week or so, or sooner if I have problems,

 

[jomanlo]

Did you read this, IA64?

Still nothing to report from my side.

Maybe they did some changes on components inside, I got my late 2013 mid January 2014, delivered from Ireland.

 

[magamo]

To add another item to the probably-safe list, I maxed out to 32GB by G.Skill's 1.35v CL9 RAM a while ago and haven't experienced any problem. As far as I can tell, there isn't a single negative report on the internet from people who installed this on 27" iMac late 2013 either. Curiously, I found reviews that say this one actually runs at 1.28v (which is within the normal range of the 1.35v label). I haven't checked the effective working voltage myself though.

Anyway, this RAM is faster than Apple's default memory and others sold as mac-friendly like Crucial's due to its lower latency. So, if a higher voltage at 32GB is actually causing a problem, this RAM might be another safer choice for someone looking for performance as well.