RAM: 1.6V vs 1.5V

ballzley · Mar 15, 2014

Hello,

Before I present my situation, this question about RAM is in the scope of CPU overclocking; I have no intentions to overclock RAM.

I am planning to purchase two sticks of RAM in dual for my 4670k build. The RAM is advertised to run at 1.6V, but I read one customer's report where his was actually 1.65V; if it were in fact 1.65V and not 1.6V, is there a concern here? The motherboard is a GA-Z87X-OC. I want to run the 4670k at around 4.7ghz 24/7. Compared to using RAM rated at 1.5V, will I have trouble with RAM rated at 1.6V? I understand this is a rated difference of 0.1V (or, in the case that it's actually 1.65V, difference of 0.15V), but I want to put this uncertainty to rest.

Thank you for reading

Dr. McCoy · Mar 16, 2014

No, you shoudn't have a problem wth the RAM - As long as you run it at it's spec'ed voltage it should be OK.
The difference in voltage (1.60v's vs 1.65v's) isn't enough of a difference to hurt anything.

ballzley · Mar 16, 2014

Dr. McCoy said:
The difference in voltage (1.60v's vs 1.65v's) isn't enough of a difference to hurt anything.

Thanks for your input.

The difference between 1.5V and 1.6V is also negligible?

usyed1 · Mar 16, 2014

Honest question: at what point is it no longer negligible and dangerous?

larrymoencurly · Mar 16, 2014

Think of it this way: RAM doesn't get rated for 1.6V because it does great on all tests at 1.5V. And if you buy 1.5V RAM but find it's not reliable, you're more likely to be able to make it run perfectly well by bumping up the voltage than if you start out with RAM rated for 1.6V.

usyed1 said:
Honest question: at what point is it no longer negligible and dangerous?

When the "absolute maximum" voltage specified by the chip manufacturer (not module manufacturer) is reached. For DDR3 memory that's no higher than 1.975V, and I think for some newer chips it's less, around 1.8V. You also have to worry about the absolute maximum voltage for the memory controller, and for the controller in Intel CPUs, that seems to be 1.65V.

ballzley · Mar 16, 2014

larrymoencurly said:
Think of it this way: RAM doesn't get rated for 1.6V because it does great on all tests at 1.5V. And if you buy 1.5V RAM but find it's not reliable, you're more likely to be able to make it run perfectly well by bumping up the voltage than if you start out with RAM rated for 1.6V.

Nyuk. I'd imagine this was the case, yes, and my only concern was somewhat addressed in your next response:

larrymoencurly said:
You also have to worry about the absolute maximum voltage for the memory controller, and for the controller in Intel CPUs, that seems to be 1.65V.

I intend to OC the 4670k, and have heard from a Fry's salesman that using RAM rated for a higher voltage in his OCd Sandy Bridge setup gave him stability problems. I plan to use these http://www.newegg.com/Product/Product.aspx?Item=N82E16820231623 and can't see it being worth using if it'll cause problems when running a mild CPU overclock 24/7.

MongGrel · Mar 17, 2014

Like was said more or less, 1.5 ram is usually just cherry picked and runs there, most ram would run 1.65
easy, but no reason too most of the time if not OCing it.

Mines a bit of an OC on it 1333 at 1720, and still have it at 1.5 the lower the better like most things voltage wise when pushing it.

Hard to go wrong with the sticks you listed there I'd say.

Woomack · Mar 17, 2014

There is no difference if memory is 1.35, 1.50 or 1.65V. All are running the same and are safe for your CPU.
There is no relation between DIMM and IMC voltages in haswells. I was running 4670/4770K up to 2.2V on couple of memory kits and it didn't kill IMC or memory ( highly not recommended to check that ).
In theory SB could have issues with higher memory voltages but I've never had any running memory up to ~1.75V ( board limit as I remember ). Intel even said that anything above 1.5V can damage IMC in SB but somehow all memory manufacturers had SB memory kits designed to work with 1.65V. I doubt they would release something that isn't safe for CPU or memory.

I was running linked TridentX memory up to 1.85V without any issues but I couldn't make them overclock higher above ~1.7-1.75V -> http://www.overclockers.com/forums/showthread.php?t=743351
It's still great kit and one of the fastest available right now.

TerranBrackiatt · Mar 18, 2014

if you're running the RAM at stock speeds, just double check the sticker (or website) for SPD or XMP profiles... heck better yet, just use CPU-Z and it'll tell you. most RAM runs SPD profiles at 1.5v, but the XMP profiles usually run at 1.6v or 1.65v. just make sure to match the voltage to the profile you're using. (IE, if the timings you're using are matched to 1.5v in the profile, setting the voltage at 1.8v will probably degrade your RAM. if the profile calls for 1.65v, then setting it lower means it probably won't be stable at the fast timings causing BSOD or fail to boot.)

sure, Intel recommends running RAM at 1.5v, but G.Skill shows on their website that they've extensively tested their XMP profiled RAM at 1.65v with NO degradation of the CPU.

TL;DR

1) check the profiles in CPU-Z (SPD, XMP)
2) match the voltage to the timings according to the profile.
3) celebrate by eating golden brown delicious crispy bacon

P.S. Woomack has done tons of research, so if you want to read up on his reviews, start with the links in his signature

ballzley · Mar 19, 2014

TerranBrackiatt said:
if you're running the RAM at stock speeds, just double check the sticker (or website) for SPD or XMP profiles... heck better yet, just use CPU-Z and it'll tell you. most RAM runs SPD profiles at 1.5v, but the XMP profiles usually run at 1.6v or 1.65v. just make sure to match the voltage to the profile you're using. (IE, if the timings you're using are matched to 1.5v in the profile, setting the voltage at 1.8v will probably degrade your RAM. if the profile calls for 1.65v, then setting it lower means it probably won't be stable at the fast timings causing BSOD or fail to boot.)

sure, Intel recommends running RAM at 1.5v, but G.Skill shows on their website that they've extensively tested their XMP profiled RAM at 1.65v with NO degradation of the CPU.

TL;DR

1) check the profiles in CPU-Z (SPD, XMP)
2) match the voltage to the timings according to the profile.
3) celebrate by eating golden brown delicious crispy bacon

P.S. Woomack has done tons of research, so if you want to read up on his reviews, start with the links in his signature

Thanks so much, I'll be sure to look out for those things when setting the RAM, and I will not forget the bacon you can be assured :salute:

MongGrel said:
Like was said more or less, 1.5 ram is usually just cherry picked and runs there, most ram would run 1.65
easy, but no reason too most of the time if not OCing it.

Mines a bit of an OC on it 1333 at 1720, and still have it at 1.5 the lower the better like most things voltage wise when pushing it.

Hard to go wrong with the sticks you listed there I'd say.

Thanks for your reassurances!

Woomack said:
There is no difference if memory is 1.35, 1.50 or 1.65V. All are running the same and are safe for your CPU.
There is no relation between DIMM and IMC voltages in haswells. I was running 4670/4770K up to 2.2V on couple of memory kits and it didn't kill IMC or memory ( highly not recommended to check that ).
In theory SB could have issues with higher memory voltages but I've never had any running memory up to ~1.75V ( board limit as I remember ). Intel even said that anything above 1.5V can damage IMC in SB but somehow all memory manufacturers had SB memory kits designed to work with 1.65V. I doubt they would release something that isn't safe for CPU or memory.

I was running linked TridentX memory up to 1.85V without any issues but I couldn't make them overclock higher above ~1.7-1.75V -> http://www.overclockers.com/forums/showthread.php?t=743351
It's still great kit and one of the fastest available right now.

2.2V

That sounds extreme. I feel confident with these sticks now, and will order a pair soon - I'll be looking more at the review you made for these Tridents! It will be my first product from G.Skill

Thank you very much for your explanations, my biggest concern was indeed the memory controller.

False Christian · Mar 28, 2014

I've been running my 2x4GB of Kingston ValueRam 1333MHz 1.5v at 1600MHz at 1.65v for months now without a problem on my Sandy Bridge platform. :drool:

ballzley · Mar 28, 2014

False Christian said:
I've been running my 2x4GB of Kingston ValueRam 1333MHz 1.5v at 1600MHz at 1.65v for months now without a problem on my Sandy Bridge platform.

Thank you for your input False Christian

It's only been a few weeks, but these Tridents at XMP aren't causing any problems either... passed memtests... I'll come back here and edit if they start acting up.

RAM: 1.6V vs 1.5V

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