Skylake's IMC Supports Only DDR3L

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IInuyasha74

Splendid
Moderator
What this article fails to mention is that most kits of DDR3 rated at 1.5V can still run at 1.35V. Just at lower clocks.
This article wasn't about how to fix RAM to work on your system, it was to discuss what Intel officially supports. Not everyone will know how to lower the voltage and clock settings on their RAM, and not all RAM will operate at lower voltages even if you lower the clock speed. That is something users will need to test for themselves on a case by case basis.
 

synphul

Polypheme
Moderator
Glad they cleared this up. Many initial reports I'd read about it indicated exactly this, that skylake's memory controller was capable of ddr4 or ddr3L (low power ddr3, not standard ddr3). When some dual memory type boards or ddr3 enabled z170 boards came out they were claiming ddr3 native support as if someone could just move their ddr3 ram to the new board and have it work just fine. It didn't make sense considering the voltage differences.

Agreed, the article isn't about fiddling with everything to get it to work and underclocking ram (having it perform worse) or anything else. People need to be made aware of the differences in the chips and the differences in the new memory standards. Half the reason to upgrade to the new platform is to upgrade, not piece it together and macgyver it with duct tape to force it to work or it defeats the purpose.
 

IInuyasha74

Splendid
Moderator


Those might work fine too, but it is hard to say. Motherboard manufacturers have very little to do with RAM support really, as the CPU's IMC controls virtually all aspects of the RAM. Intel probably had its reasons why it didn't add support for DDR4 at 1.35 V, but that RAM may work fine still. Similar with DDR3 on Sandy Bridge and Ivy Bridge, only 1.5 V was supported. Sandy Bridge only supported up to 1333 MHz, and Ivy Bridge only supported up to 1600 MHz, but other RAM kits that feature higher voltages and clock speeds have been used countless times.

Not being supported by Intel doesn't mean that it necessarily won't work, but that it is either untested or unsupported for some reason, and may cause problems.
 

Sakkura

Illustrious


The problem is that the article says people can't use their existing DDR3 memory with Skylake, which is going to be wrong in most cases. Most DDR3 can run at 1.35V just fine.
 

IInuyasha74

Splendid
Moderator


But without lowering the DDR3 to 1.35 V, it will likely cause damage over time. Again, this article was to discuss the official RAM support of Intel's IMC. This article is not to discuss ways to get unsupported RAM to run within these limitations.
 

Sakkura

Illustrious


Lowering the voltage that way is possible with most DDR3. Thus this statement in the article is misleading:

So if you don't have DDR3L on hand, you are probably better off to go ahead and spring for the more expensive DDR4.
You're advising people to spend money on DDR4 when they can most likely continue to use their DDR3 memory. That's simply bad advice.
 

Sakkura

Illustrious


Telling people they should waste their money is still bad advice, even if telling them they must waste their money would be even worse.

The sensible thing for anyone who owns DDR3 memory and is considering a Skylake upgrade to do is to check whether their DDR3 memory will run at 1.35V. If it will, then you have the option of carrying it over.
 

synphul

Polypheme
Moderator
I think it comes down to official support. Officially haswell chips only supported up to 1600mhz ram. Skylake supports up to ddr4 2133. While the cpu's may very well handle faster ram if it doesn't work don't go crying to intel or they'll just point to the officially supported specs. Same as running ddr3 @ 1.65v on haswell, it may run fine. If it 'were' to cause damage it would be similar to overclocking - physically possible but not officially supported/covered. If people choose to ignore the manufacturer's designs that's up to them and whatever success they do or don't have is another matter. So long as they know up front what they're dealing with.

I think they 'should' use appropriate memory for the platform. Worrying about 'must' spend their money on ddr4 for a ram upgrade is a bit of a moot point since no one is forcing them to go skylake in the first place. It's all a choice. I'm not sure why someone would insist on moving to skylake just to negate one of the few improvements/upgrades provided by the new platform. If they wish to stick with ddr3 why not just go devil's canyon? It's a bit like saying I'd like the latest and greatest but I don't want the features that make it the latest and greatest so in essence I want to spend a premium for cutting edge but then I want to run on old tech. Not sure what the point of that is. Similar to going to the hassle of upgrading to win10 for gaming then avoiding all dx12 games. If someone only wanted to play dx11 games, why upgrade?
 

rgd1101

Titan
Moderator


Where can we check if DDR3 memory will run at 1.35v?
 
What's "officially" supported and what usually works in the real world are often two different things. Maybe you can "officially" shorten the lifespan of your parts by what is basically overclocking, but tell that to my recently-retired LGA775 system that had four sticks of RAM running at 1.76V since 2008, without so much as a hiccup. It's just as likely the parts last until they would've been obsolete anyway.

It would've been a no-brainer to switch to DDR4 if they hadn't completely doofed it with the high latencies. But I am not that interested in paying extra for worse performance, thanks. Basically, the whole DDR3/DDR3L/DDR4 issue has been bungled by Intel to the maximum extent possible with Skylake.
 
I know that, I was referring more to the RAM itself in that case.

Basically: Overclocking can theoretically damage your components but usually doesn't unless you let it run away. This is not news.
 

rgd1101

Titan
Moderator
I think we were talking about burning out the CPU not the RAM.
And I don't think it even need to overclock, the motherboard support it out of the box and only if you under volt it to get the the lower voltage, can someone check this?
 

Sakkura

Illustrious


Since we're talking about people who have a pre-Skylake system with DDR3 memory that they want to upgrade to a Skylake system, they can just test their DDR3 memory at 1.35V on their pre-Skylake system.
 

firefoxx04

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Jan 23, 2009
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To the people arguing about using ddr3 > ddr4... did you ever stop to think that maybe just maybe the top of the line 1151 boards only use ddr4 and that the ddr3 boards are probably a tier or two lower?

If you are jumping on skylake this early in the game, its probably for a high end system brand new everything. If you are building a low power system.. then haswell/ddr3 will do you just fine.

DDR4 is hear people, get over. If you dont want it, stick with tried and true Haswell until prices drop on ram and boards.
 

rgd1101

Titan
Moderator


So you are assuming pre-skylake system can handle 1.35V memory without getting bsod.
 

rgd1101

Titan
Moderator


Even for the DDR4 so far 3000MHz and greater are 1.35v not 1.2v. Just something to think about, sound like it does work, the question is if and when it burnout the IMC.
 

synphul

Polypheme
Moderator
As far as the latencies going up with ddr4, that's to be expected. It's happened with every version of ddr memory so it shouldn't come as a surprise. At a certain point the increased frequencies, even with a slightly higher latency, do perform better. Corsair's xms2 ddr2-800 had timings of 4-4-4-12. With their xms3 ddr3 1600 the timings went up to 9-9-9-24. Cas latency in ddr4 had increased to around 13 for ddr4 2133. Why the tears over the latency of ddr4 and not the tears over the ddr3 latency increase over ddr2?

Upgrading yet fighting to hold onto old hardware that the upgrade is supposed to improve upon just doesn't make sense to me I guess. It's like upgrading a gaming system yet hanging onto the old pcie 2.0 gpu and expecting huge improvements. Why go to the trouble, spend the money etc for the improvements if people are going to negate them. May as well hang onto what they've got. Maybe it's just me but I thought the point of upgrading was replacing the old hardware with newer. If current hardware is satisfactory, no point in upgrading.

The same folks recommending to go skylake instead of haswell/devil's canyon are suggesting a more expensive platform in terms of motherboard, cpu, etc with little gains over devil's canyon but then balking on a few dollars for the newer ram. Pushing for or recommending change while at the same time insisting on stagnation seems to be at odds with one another.
 

rgd1101

Titan
Moderator
[strike]Not me. Was thinking of getting DDR4-3000, but all I found are 1.35v. Unless they come out before when I build mine, probably going to get 2800 instead[/strike]
Nevermine, was looking at 2x8GB, there are 1.2v 4x4GB
 
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