DDR4 for X99-S with 5820k - OC?

[daolo]

Hello,

My first post over here at overclockers.

Have tried to pinpoint which path to take but can't really get it right.

My current cpu is a i5-750k so I haven't really been into oc-business for a while..!

Now I'm changing to an Asus X99-S with 5820k - and my intention is to overclock it as much as possible with a Fractal Design Kelvin S36 (AOI with 360 rad).

I've heard that 5820k probably tops at 4.5ghz, so I guess that will be my goal.

Now to my issue... What mem do I choose? I've looked at Corsair LPX because of good availability and fair pricing (at least here in Sweden).
But, what spec? 2666 mhz? 2800 mhz? Afaik 2666 is the limit for the cpu, then I need to change bclk. Will 2800 mhz just complicate things? I guess it's still possible to run the 2800 mhz specced mem in 2666 mhz instead?

What are your suggestions? (Can/should I reach 4.5 ghz without altering blck and thus will have an easier time using mem at 2666mhz?)

Hope you can clear some things up for me!

BR
/David

 

[Woomack]

Any DDR4 will be good. Memory has separate ratios so it won't affect CPU overclock. Also every DDR4 should work on ASUS boards as all DDR4 kits are based on 3 popular IC and every motherboard manufacturer already tested most popular memory kits.

Corsair is kinda overpriced, you can find other brands cheaper. G.Skill or Kingston are cheaper and overclock better. If you still want Corsair then LPX 2666 1.2V have 2800 1.35V XMP profiles and should work without issues on ASUS boards.

Here are my Corsair LPX 2666 C15 tests -> http://www.overclockers.com/forums/...e-LPX-4x4GB-DDR4-2666-CL15-CMK16GX4M4A2666C15
Couple of other DDR4 tests can be found here -> http://www.overclockers.com/forums/showthread.php/732290-Woomack-s-memory-test-list

 

[daolo]

[QUOTHX428C14PB2K4/16

=Woomack;7775713]Any DDR4 will be good. All have the same general specification. Corsair is kinda overpriced, you can find other brands cheaper. G.Skill or Kingston are cheaper and overclock better. If you still want Corsair then LPX 2666 1.2V have 2800 1.35V XMP profiles and should work without issues on ASUS boards.

Here are my Corsair LPX 2666 C15 tests -> http://www.overclockers.com/forums/...e-LPX-4x4GB-DDR4-2666-CL15-CMK16GX4M4A2666C15
Couple of other DDR4 tests can be found here -> http://www.overclockers.com/forums/showthread.php/732290-Woomack-s-memory-test-list[/QUOTE]

Ok - thanks for your quick reply.

So you're saying that any freq/cl will do - it's rather a question of price/cooling/warranties and such?

Will there be any fix for the 2666mhz+ from intel or is it hardwarerelated? (Just thinking - if the choice really doesn't matter atm . it might be changed in the near future?)

Edit: Ok to run 2800 mhz mem in 2666 mhz? (Bclk 100.)

Would Kingston hyperx t2 Predator 2800 mhz cl 14 be a nice pic?

Or GSkill ripjaws 4 2666 mhz cl15 a better one?

 

[Woomack]

I made tests of Kingston 3000 C15-16-16 kit which is about the same as 2800 CL14 or 2666 CL13 ( just different XMP profiles and higher clock is guaranteed to run so high ).
Almost every DDR4 at 2666 or higher clock will set 125 bclk using XMP profile. Corsair 2666 which I was testing, was using 100 bclk at 2666 but 125 bclk at 2800. G.Skill 2666 C15 ( test also in 2nd link of my 1st post ) was using bclk 125 at 2666 C15 profile.

100, 125 or even 167 bclk straps should work without voltage changes but effective memory clock may change depends which memory ratio will be available.

On ASUS boards ( I think that X99-S too but I'm not sure ) working memory ratios are x21.33, x24.00, x26.66, x30.00, x32.00 so memory effective clock will be memory ratio x bclk. I think that some manufacturers are protecting themselves and use max x24 memory ratio in case of compatibility issues with some boards that's why G.Skill 2666 kit is 21.33 x 125bclk. On non-ASUS boards max memory ratio is usually x26.66.

 

[daolo]

I made tests of Kingston 3000 C15-16-16 kit which is about the same as 2800 CL14 or 2666 CL13 ( just different XMP profiles and higher clock is guaranteed to run so high ).
Almost every DDR4 at 2666 or higher clock will set 125 bclk using XMP profile. Corsair 2666 which I was testing, was using 100 bclk at 2666 but 125 bclk at 2800. G.Skill 2666 C15 ( test also in 2nd link of my 1st post ) was using bclk 125 at 2666 C15 profile.

100, 125 or even 167 bclk straps should work without voltage changes but effective memory clock may change depends which memory ratio will be available.

On ASUS boards ( I think that X99-S too but I'm not sure ) working memory ratios are x21.33, x24.00, x26.66, x30.00, x32.00 so memory effective clock will be memory ratio x bclk. I think that some manufacturers are protecting themselves and use max x24 memory ratio in case of compatibility issues with some boards that's why G.Skill 2666 kit is 21.33 x 125bclk. On non-ASUS boards max memory ratio is usually x26.66.

Ok great, thank you for all the valuable information!

I will probably go for the Kingston Hyperx Predator 2666 mhz then, 4x4gb.