Do Kaby Lake Xeons support DDR4-2133 even though Ark specifies DDR4-2400 support?

[nasnut]

I have a NAS server built on an ASRock Rack 236 WSI MB. Currently, it is populated with a Skylake Xeon E3-1245 v5 CPU and 32 GB DDR4-2133 Unbuffered ECC RAM. I am considering upgrading to the Kaby Lake E3-1245 V6 to future proof for 4K 10-bit content when it becomes more widely available. Skylake V5 supports 8-bit HEVC but only partially supports 10-bit HEVC.

My question has to do with RAM compatibility. The Kaby Lake V6 supports DDR4-2400 RAM. Does that mean it will not work with the slower DDR4-2133 I have in the server? I do not want to upgrade RAM right now at current prices. I got the DDR4-2133 for $178 in late 2016. DDR4-2400 would cost me over $400 at current prices. Can I use a Kaby Lake CPU with DDR4-2133 or is DDR4-2400 required? I assume it should work with the slower RAM, but, these days, no assumption is safe.

 

[MeanMachine41]

Hi nasnut

Skylake Xeon E3-1245 v5 CPU officially supports up to 64GB of DDR4-1866/2133MHz RAM.
MB specs indicate official support for Dual channel DDR4 2133Mhz however 2400Mhz are listed on the MB QVL and have been tested with Hynix RAM at 2400MHz.
In simple terms, they may or may not work at 2400MHz out of the box.

 

[nasnut]

Hi nasnut

Skylake Xeon E3-1245 v5 CPU officially supports up to 64GB of DDR4-1866/2133MHz RAM.
MB specs indicate official support for Dual channel DDR4 2133Mhz however 2400Mhz are listed on the MB QVL and have been tested with Hynix RAM at 2400MHz.
In simple terms, they may or may not work at 2400MHz out of the box.

Thank you for your answer MeanMachine41. Yes, I know the Skylake Xeon supports DDR4-2133 and may not support DDR4-2400. I have DDR4-2133 in my server now. My question is, if I upgrade to a Kaby Lake Xeon V6, will it still support the DDR4-2133 I have installed or does it require DDR4-2400? Motherboard specs say DDR4-2400 is only supported with Kaby Lake V6, but, will Kaby Lake work with DDR4-2133?

 

[MeanMachine41]

If it's Xeon Processor E3-1505M v6 then official support is for 2400MHz.
Never tried it with 2133MHz so can't say 100%. Scaling up is a bigger problem than scaling down.
It will depend on Bios and that's the risk you take.

Someone else may chime in with a definitive answer and hopefully from Intel.