Unstable Memory Clock issues

[Kpwn3r]

I have 8x4 GB sticks of DDR4 corsair vengance ram rated for 3200 MHz. By default in the bios, the clock speed is set to 2133MHz, but when i try to increase the frequency up to anything above 2600, the system becomes unstable and will crash under load. Im unsure of what to do, since i want to be running near or at the requency the memory is rated for. XMP is not enabled, not sure if that would make a difference. I do have a 5960x CPU in there, and i have it overclocked from 3.0 to 3.7 GHz, runs stable at 60 C under full synthetic load. I have the bios set to automatically control voltages. Let me know if you have any advice. Thanks.

 

Specs:

-Motherboard: Asus X99-A/USB 3.1

-CPU: I7-5960x overclocked to 3.7GHz

-RAM: Corsair Vengance DDR4 3200MHz 32 GB quad channel

-Video Card: 2x GTX 960 in SLI

-PSU: 800W EVGA Gold Certified

 

[Chris Pratt]

2 minutes ago, Kpwn3r said:

XMP is not enabled, not sure if that would make a difference

Yes. It makes a huge difference. You can't just up the clocks. There's timings and voltages that have to go along with that. XMP is literally a profile for overclocking the RAM, which takes care of all this. Just enable XMP. 

[Kpwn3r]

16 minutes ago, Chris Pratt said:

Yes. It makes a huge difference. You can't just up the clocks. There's timings and voltages that have to go along with that. XMP is literally a profile for overclocking the RAM, which takes care of all this. Just enable XMP. 

For learning purposes for me, why do they rate memory at a certain speed and then have it at such a small base clock by default in BIOS. Is 3200 just the max it will “overclock” too or does it work some other way. Thanks

[Chris Pratt]

21 minutes ago, Kpwn3r said:

For learning purposes for me, why do they rate memory at a certain speed and then have it at such a small base clock by default in BIOS. Is 3200 just the max it will “overclock” too or does it work some other way. Thanks

The rated speed is the XMP speed. The "default" speed, and what's given in CPU and mobo specs is the JEDEC standard that's supported. JEDEC is the standards body behind DDR (among other things) and they define the spec for things like DDR4. Right now, the highest JEDEC standard for DDR4 is 3200MHz, but that's relatively recent. It was 2666MHz before that, and 2133MHz before that. Depending on the combo of CPU and mobo, you'll get one of those three as your out of the box RAM speed.

 

Because it's a standards body, JEDEC is both conservative and slow to react, so as manufacturers began to be able to easily exceed the officially supported specs, XMP was created (by Intel) as a way to allow pushing the RAM clocks past the standard. It is very literally an overclock of the RAM, but one that is safe and easy, because the RAM is good enough to go much higher in virtually all scenarios.

 

It's not like something like a CPU, where the manufacturer has pretty much already pushed it as far as it can go, and you're just trying to push it even more. RAM speed is artificially limited by the standard, and can easily do much more.

 

Also, the rated speed is just the XMP profile, which is basically the best it'll do at 1.35V (there's a lot more to it, but that's the simplistic version). DRAM voltage can be pushed as high as 1.5V in some cases, so there's sometimes OC headroom even above XMP. That's when you get into more traditional OC territory, though, where you can potentially introduce instability. You can think of XMP as an "official" OC, like graphics cards that come "overclocked" out of the box. The manufacturer has already made sure that they can reach at least that level of performance, but that doesn't mean it's the best that's possible.

[Cyracus]

32 minutes ago, Chris Pratt said:

DRAM voltage can be pushed as high as 1.5V in some cases

It is best not to exceed the voltage of the xmp profile of your memory unless you know what you're doing, degradation can begin under 1.4v for some ddr4 memory chips.

[Chris Pratt]

Just now, Cyracus said:

It is best not to exceed the voltage of the xmp profile of your memory unless you know what you're doing, degradation can begin under 1.4v for some ddr4 memory chips.

Definitely. I wasn't saying that as a recommendation of something you should go do. The OP had asked if the rated speed was the "max", and so I was addressing that. Technically, no. Most RAM can go higher even than XMP, but like with any OC, you need to know what you're doing to take it there.