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danseva · ‎11-26-2016

Hi guys, my first post here 🙂
So I have an i7 3820 paired with an P9X79 WS and 32GB (4X8GB) corsair vengence pro ram (CMY32GX3M4C1600C9R).
With everything at stock sometimes the system views only 3 of my 4 ram sticks.
The faulty one appears "abnormal" in bios at SPD info. Again this only happens sometimes and only at cold boots. And it only happens to one ram stick no matter in which slot I add it in.

Tried drastically increasing voltages VCCSSA (1.3v), VTT(1.3v), DRAM(1.75v) , adding manually all the memory timings, running the memory at a lower frequency but nothing worked. The only remedy I could find was to put DRAM training on "ignore" and this way the system always sees the full memory.
Now my question: Is this a good practice?
I also need to mention that the system passes all stability tests I could throw at it: memtest, prime95, aida etc.

Hope someone can help me 🙂

Korth · ‎11-26-2016

It could be an underspec or mismatched DDR3L stick.

I would try cleaning the DDR3L connectors with an electrical contact cleaner. Stabilant-22 or DeoxIT work best. Non-perfumed isopropyl works, but it's a weak solvent so some scrubbing might be required. The old pink eraser trick can indeed scrub contacts clean, but it's widely discouraged due to ESD concerns - I'll admit that I think the risk of ESD damage is vastly overrated, but my main concern is that the rubber can also erase a few microns of gold plating off the contacts.

Clean out the RAM slots too, if you can. But if you're not confident about this then it's probably best to not tamper with what works.

I don't know what "Ignore" will do to memory training. My experience has always been that quality RAM doesn't really need training. But then again, I tend to buy overrated memory and let it run at the fastest speeds natively-supported by the chipset PCH or CPU iMCs.

You could also try replacing ye olde CR2032 motherboard battery. I know it seems irrelevant, but it can magically fix all sorts of apparently unrelated system ailments on older motherboards. 3-packs cost $1 at the local Dollar Store, lol.

"All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others." - Douglas Adams

[/Korth]

danseva · ‎11-26-2016

Thank so much for the fast reply!
Sure I've cleaned the ram nicely (without any luck). Will try to replace the battery soon.

"Ignore" means that if the motherboard find "anomalies" in a ram stick it doesn't closes the channel (so that's why I know is a "training" thing, because with it on "ignore" it always works).

Is a very frustrating thing to test because 9/10 times it works perfectly and suddenly it only sees 3 sticks of ram....

Korth · ‎11-26-2016

Is your i7-3820 overclocked?

And is your PSU still performing fully up to snuff?

"All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others." - Douglas Adams

[/Korth]

danseva · ‎11-26-2016

For testing purposes everything is stock. My PSU is a Corsair CX750M (not top tier but gets the job done).
The system manages to pass all stability test I can throw at it (even with memory training on "ignore" and all 4 ram dimms active)

Is a really strange issue isn't it 😛

Korth · ‎11-27-2016

I don't call it "strange", I call it "intermittent failure", lol.

I'm willing to rule out misconfiguration. So I think a component (or an interface between components) is failing under thermal or electrical stress, especially under sustained heavy load.

Try replacing your mobo battery, possibly a cheap fix which cannot hurt (unless you forget to note down all your BIOS settings, lol).
Try a different PSU if you can, possibly a fix and definitely a way to determine if it's bad RAM or bad PSU.

I'm thinking that if Ignore works perfectly then just keep using it, lol. There is no substitute for success!

"All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others." - Douglas Adams

[/Korth]

danseva · ‎11-27-2016

Sure will try the battery thing soon 🙂

Thanks so much for the help!

danseva · ‎12-07-2016

Well I think is stable now (cannot confirm without more tests of course).
But had to put the VCCSA to 1.4 and its LLC to extreme (so the effective voltage is a bit over 1.4).

Not sure this is a good idea (all the forums posts are screaming not to go over 1.2) but will see how it goes.....

Memory training