I think my 27" Late 2013 memory is overheating :\

[jordanm86]

If you look to the pictures, you'll see that the modules from Amazon are DDR3 and those from Crucial are DDR3L (L= Low Power), so probably the overheating is related to this diffrence.

Is the iMac definitely shipped with DDR3?

If the iMac was not capable of handling DDR3, I'm sure Apple would have mentioned it?

The Macbook Air specified LPDDR3 and the Macbook Pro Retina specifies DDR3L on the tech specs but the iMac just states DDR3.

I've ordered DDR3 (not DDR3L) for my iMac (neither have been delivered yet).

 

[X-Ravin]

Exactly, the MBP Retina specifies DDR3L on the configuration page of the website but the iMac shows DDR3 :-/

Haswell can handle up to 1.5v ( +5% so a max of 1.575v).

Well despite what I said I can confirm the same issue on my iMac with Crucial RAM from Amazon. That sensor does indeed jump up over 200 degrees within minutes of running a Prime95 torture test.

Looks like we do really need the DDR3L RAM.

 

[ian2000]

Looks like we do really need the DDR3L RAM.

The Kingston KHX16LS9P1K2/16 RAM I mentioned in post #73 is 1.35V DDR3L, so I'm not sure that's the issue, if there is one!

 

[X-Ravin]

The Kingston KHX16LS9P1K2/16 RAM I mentioned in post #73 is 1.35V DDR3L, so I'm not sure that's the issue, if there is one!

Oh whoops I missed that post, good to know.

 

[Chipster21]

Is the iMac definitely shipped with DDR3?

If the iMac was not capable of handling DDR3, I'm sure Apple would have mentioned it?

The Macbook Air specified LPDDR3 and the Macbook Pro Retina specifies DDR3L on the tech specs but the iMac just states DDR3.

I've ordered DDR3 (not DDR3L) for my iMac (neither have been delivered yet).

The iMac is shipped with DDR3L (1,35V not 1,5V) , I'd suggest you to exchange the DDR3 for DDR3L. Mine are DDR3L from Crucial and they are working wonderfully.

 

[jordanm86]

The iMac is shipped with DDR3L (1,35V not 1,5V) , I'd suggest you to exchange the DDR3 for DDR3L. Mine are DDR3L from Crucial and they are working wonderfully.

Oh no, what a pain :-(

Is anyone operating DDR3 1.5v without issues?

I just think it's really weird that Apple haven't mentioned it at all... even in their Late 2013 iMac Memory Spec Documents (link below) it doesn't state DDR3L... just DDR3 and not mention of a voltage limit :-/

http://support.apple.com/kb/HT5908

The other thing I don't get is if the DIMM slot can only handle 1.35v, then surely that is all the RAM module can draw from it (so a 1.5v would either perform poorly or not at all rather than overheat).

On the other hand, if you put a 1.35v module into a port supplying 1.5v, the excess would need to dissipate and that would cause heat?

Is it possible that a few people just got bad RAM modules and also surely the sensors inside the machine would either kick the fans in very high or cut the machine off (like I found out the iPhone does after my brother left his in the sun ).

 

[Arfdog]

Did you design the ram, are you the company who designed the ram for this specific computer? This is a haswell specific machine not a 2012 machine that these might work on. I'm sorry but Crucial would not have a compatibility chart with only the CT4941624.

I also wouldn't spend 2-3k on a computer to cheap out and stick ram in my computer that is the wrong part number. The op didn't know, but you're blantfully telling people that its ok. It is not ok. If you want to risk screwing up your expensive machine go right ahead. Apple logs all hardware Id's and links it to your apple account. If repair reps are smart enough to look that up they will see that you used incompatible ram thus voiding you warranty you wont get it fixed for free, but hey its your computer do as you wish.

Just don't come on here telling people that might not know anything (or a little) about computers and let them think its ok to run ram thats not on the comparability list. If it was compatible it would be on the Crucial list of compatible ram. It is NOT. Their is a lot more that goes into the design and compatibility of ram other than the specs you see on the for sale page.

Since when does installing incompatible RAM cause iMacs (or any PC) complete and utter destruction?

 

[Arfdog]

The list is on Every Manufacture that sells ram for Imacs. I'm not talking about Apple keeping this list, I'm talking about the manufactures of the ram like Crucial. Crucial list is on their website and the only approved one is this one

This is no Myth, if apple figured out that the ram malfunctioned/sparked or overheated and it also caused the motherboard to fail, apple employee's will look up the model number of the ram on crucial website to see if its their compatible list and decide what to do from their. If its not on the list and its stated compatibility is with the 2012 model and not the 2013 model the warranty service stops right their and it gets shipped back to you. Then it becomes User Error and your 100% responsible for all damage caused by your mistake.

http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=81CE351CA5CA7304

Again, in what computer system design would incompatible memory cause the computer to detonate into a nuclear fireball?

Computers have power supplies that protect and filter electricity. A wacky RAM module won't suddenly set all 120 volts and 10 amps rampaging through the motherboard...

What will actually happen is the RAM controllers will sense incompatible signals and tell you, on screen, "incompatible".

 

[cpc6128]

Has anybody successfully installed a Corsair Vengeance 1.5v Ram (Model CMSX16GX3M2A1600C10) into the latest 2013 iMac with no issues whatsoever?

My iMac is a BTO (i7) and won't be here for another week or two.

Just deciding whether to sell the 1.5v Vengeance ram and get a 1.35v ram to be safe?

 

[BulletToothTony]

Has anybody successfully installed a Corsair Vengeance 1.5v Ram (Model CMSX16GX3M2A1600C10) into the latest 2013 iMac with no issues whatsoever?

My iMac is a BTO (i7) and won't be here for another week or two.

Just deciding whether to sell the 1.5v Vengeance ram and get a 1.35v ram to be safe?

I also am very interested in this, since crucial seems to not be delivering this generation, at least not yet

 

[jomanlo]

I just want to share my results because I was reading a lot over the forum before upgrading the ram from my Late 2013 Imac and I decided to have my own experience with my machine.

I ordered the Imac 27 with "only" 8Gb in order to replace the memory myself. I received it in January 2014 with 2x4Gb DDR3L ram, it means 1,35v.

I took out the DDR3L 2x4Gb 1,35v and replaced it with DDR3 4x8Gb 1,5v

As ram I have now inside:

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

I ran the Apple complete hardware check and 3 rounds of Memtest, there were no errors. So for the moment working good.

However for my personnal use I did not notice any increase of speed (application launch) maybe due to the fact that I am using a PCI-SSD.

If you want certified ram for Imac's Late 2013 you can use:

KINGSTON KTA-MB1600L/8G
8GB, DDR3-SODIMM, PC3-12800 (1600MHz)