I am HIGHLY confused about Skylake/Kaby Lake memory speeds

[jana519]

... and I need someone to set me straight. Are DDR4 memory speeds controlled by the CPU or the motherboard chipset, which is it? I've been hearing people say BOTH for the last 3 months and it's driving me absolutely crazy!

 

[VirtualLarry]

Both. That's how Intel segments their market.

If you have a Z-series board (Z170, or Z270), then you can dial in whatever overclocked RAM (XMP) speeds that your RAM and CPU memory-controller will handle.

Otherwise, you are limited to the "base" RAM speeds, which are 2133 for Skylake and 2400 for Kaby Lake.

 

[jana519]

I don't know why this was so difficult for me to wrap my head around...

Thank you?

 

[jana519]

Oh wait, now I remember why. Because 100 series non-Z motherboards (H110, H170, B150) state the supported memory speed as DDR4-2133, but with Kaby Lake you can run 2400. That's a property of the CPU.

On the other hand, with Z170 and Z270, the CPU memory speed is irrelevant. THAT's why I was confused about this.

Thank you for clearing that up!