Skylake + DDR3 - How long before problems?

Gron113

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Apr 1, 2016
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I got a 6600k and a ddr3 capable motherboard so i didn't have to buy new ram, a while ago. Since then I have it OK at 1.35v for the RAM, which is apparently OK for the IMC in my CPU, as issues and controversy have risen as a result of using DDR3 with skylake.

I hope to be getting a new motherboard with some proper RAM very soon, but my question is: If I put the voltage back up on my RAM and run it normally, how long will i be running it before my CPU gets damaged? Or is it an instant effect?

Thanks
 
Solution
No real way of knowing. It might cause damage in a year, two years, 3yrs, or you might upgrade before it does. It's hard to document something that may be an issue slowly created over time. Things like electromigration tend to happen over time and not immediately. It may result in things like a random error here and there eventually getting worse. How soon that happens and how bad it happens is likely to vary from cpu to cpu just based on normal deviation tolerances during manufacturing.

As die's shrink (65nm, 45nm, 22nm etc) the likelihood somewhat increases. They try to safeguard against it using different techniques but it does become more problematic due to the thinner smaller traces. Between the rate of failure and length of time...
No real way of knowing. It might cause damage in a year, two years, 3yrs, or you might upgrade before it does. It's hard to document something that may be an issue slowly created over time. Things like electromigration tend to happen over time and not immediately. It may result in things like a random error here and there eventually getting worse. How soon that happens and how bad it happens is likely to vary from cpu to cpu just based on normal deviation tolerances during manufacturing.

As die's shrink (65nm, 45nm, 22nm etc) the likelihood somewhat increases. They try to safeguard against it using different techniques but it does become more problematic due to the thinner smaller traces. Between the rate of failure and length of time it takes to fail it's so hard to test that it's often 'guessed' using various laws and algorithms.

https://en.wikipedia.org/wiki/Electromigration
http://www.eetimes.com/document.asp?doc_id=1280370&page_number=4

My guess would be with a die shrink from 22nm to 14nm it's part of the reason intel warns against it, even if they're erring on the side of caution. They don't want to have to replace anymore cpu's than absolutely necessary so they lay out guidelines to reduce risk. Potential risk doesn't mean likely risk but risk none the less. It's up to you if you think it's worth it.

It wouldn't be the end of the world but 'if' it damages your cpu you're out around $240 to replace it. Some may disagree, but ddr4 has been around the same price as ddr3 for awhile now. My personal opinion is saving $40-45 for an 8gb set of ram isn't worth potentially having to replace a $240 cpu.

Edit: Just to comment on what SkittishGaming mentioned, that's part of the problem. The motherboard companies have made skylake compatible ddr3 boards but the potential risk involves the memory controller. In the past when it was part of the motherboard, so long as they guaranteed and warrantied something great. Skylake's memory controller is part of the cpu however so it's not really up to the motherboard manufacturer to say 'sure, it's fine, go ahead'.
 
Solution


Didn't know its that big of a problem!
 
There is absolutely no problem with using Skylake with DDR3L, Skylake is designed for use with 1.35V.

Where the 'controversy' lies is with people using standard 1.5V DDR3 with Skylake because they already have it or is slightly cheaper.

Synphul's comment only applies to standard 1.5V (or above) DDR3. Since you are using the correct DDR3L (or standard DDR3 which still runs fine at 1.35V, which is functionally the exact same thing), it does not apply to you.
 
It may or it may not be. There haven't been any real validated reports of it, nothing as definitive as "so I built my new skylake pc with ddr3 and the cpu fried". Sometimes cpu's ship defective or become defective, for a variety of reasons. It's a relatively low percentage but it's a percentage none the less. When someone rma's a cpu that's defective and they ran it with ddr3 ram, it could have been a basic defect and it could have been because of the ram. There's no real readout that says what part of the cpu failed or why.

Generally a degradation in a cpu takes time. An aggressive overclock has the same potential, after awhile maybe the cpu can no longer reach a specific oc. Maybe it begin generating errors or the oc has to be backed off and voltage turned down. It's a bit like trying to guess and solve the question "I bought my cpu today and overclocked it, how long before it dies". Tomorrow? Next year? 6 years? There's no one to ask how it will perform in 3yrs because skylake hasn't existed for 3yrs yet.

Intel previously had the memory controller as part of the pch. With skylake they integrated it into the cpu itself so the motherboard manufacturer has no control over it. They provide the socket, the traces and pathways to the ddr slots but they no longer provide the controller. I'm not saying it will absolutely kill the cpu, just going by intel's warnings. They made the imc so I tend to listen to them.

In the past when a motherboard included the controller, if something goes wrong I could say 'hey, your mobo stated it would work with this and it didn't', they'd issue an rma. Doubtful their warranty covers other components like the cpu, so long as the mobo is fine they've got no reason to warranty anything and you're left with a cooked cpu. There have been other issues with mobo manufacturers going a bit rogue, offering up features against intel's wishes such as overclocking on non k cpu's or with non z motherboards.

I'm not sure the specific reason intel was quick to lock it down, maybe because they were afraid to lose money if people could buy cheaper cpu's and overclock them reducing sales for higher clocked or k series cpu's? Or is it because the non k cpu's were binned out for the particular specs and intel is concerned if people go overclocking them left and right there will be a large increase in failed cpu's they'll have to deal with? It could be they've been a bit more adamant this time around because of the die shrink, maybe they know something we don't. Or a bit of both reasons. Intel did go out of their way though to warn against using higher voltage ram beyond ddr4/ddr3L with skylake.

Edit: +1 to what InvalidError said, I was referring to 1.5v (or higher depending on the ram) standard ddr3, not the lower 1.35v ddr3L (low voltage ddr3). I thought the question was regarding setting currently undervolted ddr3 back to 1.5v stock voltage.
 

The second part of OP's question was indeed about returning RAM to normal voltage but since that is after "getting a new motherboard with proper RAM very soon", I'd expect the "proper RAM" to be DDR4 as he wouldn't need a new motherboard to use DDR3L.

Unless OP has other motives for changing the motherboard, I'd simply stick with the under-volted DDR3 on his current motherboard.