2133 is the base memory speed. Everything else is factory overclocked.

The manual says 2667 is supported.
"The memory controller can support memory speeds from 1200 through 2667 via multiplier adjustment. Anything above that will require BCLK adjustments."
manual --> www (dot) evga (dot) com/support/manuals/files/BIOS/151-HE-E999_BIOS_GUIDE.pdf
 
But Intel says their CPUs support up to 2133 MHz.
ark (dot) intel (dot) com/products/82931
This is a link to the 5930k as an example.

2133. That is the base, and highest you can buy before overclock. 2400 is overclocked. So far, it seems like sets are coming out up to 3300mhz. But no matter HOW you look at it, 2133 is the base and highest you can go without it being factory overclocked. If you buy a set that says 2400,and set it to stock, it will run at 2133. If you enable the xmp profile, it will boost to 2400. That goes for ANY number you pick beyond 2133.

Yep, exactly. Keep in mind, overclocking the Ram requires you to change the bclk, changing the base clock overclocks everything, and some things do not like having the base clock changed. Running a 125 base clock can supposedly cause damage to hard drives and SSD, but I have never messed with it so that part I do not speak on knowingly.

You can overclock your Ram up to 2667, which is extremely easy to do with 100mhz bclk. Any higher requires the higher base clocks.

When you pay for 3000mhz Ram, you are paying the company to guarantee the overclockability of the Ram, up to that speed, at the rated voltage it shows.

I bought 2400mhz Ram, and it immediately (with manual settings, not xmp profile) overclocked to 2667 without any voltage increase.

Macto1990
Is setting the XMP Profile realy called OC already?

Its a OCing profile setting.  It automatically OCs the ram to its advertised specifications.

Macto1990
Is setting the XMP Profile realy called OC already?
I would not call something OCed when everything runs on clocks that are written on the packaging.

 
Think of it this way, it is the same thing as buying an SC graphics card.  It is the exact same card, but the Bios is set to run it at higher clocks. If the Manufacturer made it dual bios, one with standard NVidia clocks and one with EVGA overclocks, the card is still being overclocked when you switch over from the NVidia Bios to the EVGA BIOS.   It's the same with ram.

JDog2012
Hello,
 
I'm curious what the highest base memory speed for RAM the board can support WITHOUT overclocking. All specs i read have different numbers followed by a "+ (O.C.)"

OK, to clarify this...
- Baseline speeds for DDR4 according to JEDEC are 1600, remember DDR3 was 800.
- X99's run at a base of 2133, with 8 modules this will be reduced, the info at Ark is a bit odd and not presented they way it normally is, however it appears that in a 8 DIMM config the base speed would be 1866.
Anything above that would be overclocking as that is the memory controllers base speed, but most can go higher.
- The base speed you can set in the memory controller (via multiplier) is 2667, and so far from my testing, most everything will reach this speed.
- Above that speed will need changed in the BCLK, just like above 2400 on X79 or 2667 on Z97.
 
Hope that clears it up for you.