DDR4 Timings help

Hi guys. Please bear in mind I'm a complete noob when it comes to OC'ing and stuff like memory timings and such and I would like a little help if possible.

 

I've just set up my new x99 PC and I'm having a little trouble with the ram timings and things.

 

The kit I got was Corsairs DDR4 2800MHz 16GB 4 x 288 DIMM Unbuffered 16-18-18-36 DOMINATOR Platinum 1.20V (CMD16GX4M4A2800C16)

 

I've OC'd my cpu (5820k) to 4.4 stable at 1.25v. Left the BLCK on auto, just changed the multi. On running cpu-z it's telling me that my ram is running at a DRAM frequency of 1066.5 and that the timings are 15,15,15,36 :(

 

Like I said I'm still learning when it comes to this stuff so forgive me if I've missed something somewhere but why is my ram not running at 2800 with timings of 16,18,18,36 like Corsair have said?

 

Thanks all for any advice/help. :)

You are likely looking at the data rate = 1066MHz. DDR is Double Data Rate which equates into the standard default 2133MHz for DDR4. So, nothing is wrong and you are running at the normal default speed.

 

XMP or Extreme Memory Profile is a set of timings encoded onto your memory modules that allows you to easily switch to an alternate set of timings. It's a preset. On your memory you likely have one for 2800 and another for 3000 MHz. These can be enabled in the BIOS from the EZ BIOS page on the left side or also within the advanced settings categories. However, read below before you do.

 

If you've just got your system up and running, I would suggest leaving the memory at the standard 2133 for a few weeks to make sure everything else is running stable. It will also give you some idea of how your system performs and a basis for future evaluations of any increase in memory speed. Before you start changing the memory settings, do your self a favor and make a system image of your C: drive. It's a lot easier to restore from that than resinstall windows and everything else if things go wrong.

 

There are a few rules you have to play by when overclocking your memory. The newest BIOS will now allow you to try and run 100 BCLK at 2600-2800, but there is no guarantee it will be stable. There were substantial difficulties at the 125 BCLK already for many people attempting to run 2666 or 2800. When you change the BCLK to 125, you will also change your CPU overclock and you will need to compensate across multiple categories. When you are ready to try and overclock your memory, I suggest you start at ~2400 and see how it goes. Most people are very stable at that speed and it doesn't require any re-tuning of your CPU overclock. The other option is to let the AI Suite do it for you. It will likely give you a 4.4 speed with 2400-2450 memory speed when the stronger settings are requested. It will also likely run higher timings and higher voltage than you really need, but it does give you a place to start. Most people aren't going to be able to discern the difference between 2133 and 2400 in their usage. Do be in too much of a hurry to crank up your memory speeds.

short question from me:

Is the timing more efficiently with 15-15-15-36 or with 16-18-18-36 at 2400MHz?

In general lower numbers are better, but the primary timings alone don't tell you the whole story (there are many more timings than that, with varying impact on memory performance).