Mixing 2400 and 2666 Mhz DDR4 RAM

[crazygambit]

I have 2 sticks 8GB RAM, this one if it makes any difference: Kingston HyperX Fury Red 8GB 2400 MHz DDR4 RAM,

https://www.amazon.com/Kingston-Technology-HyperX-2400MHz-HX424C15FR2/dp/B06XKSPTH7

 

I'm looking to add more RAM to my unraid server and for some reason in my neck of the woods 2666 Mhz DDR4 RAM is cheaper at the moment. I'm not super concerned with RAM performance, but I want to know if it's safe to mix and match. I'm OK with the new RAM running at the lower speed, I'd just rather not pay more for 2400 RAM.

 

On the Kingston page it says the RAM automatically overclocks to 2666. I honestly have no idea at the speed it's currently running, I just plugged it and turned the machine on. I'm super novice when it comes to motherboard settings, timings, overclocking and all that.

 

Does anyone have any insight they would like to share regarding this?

[JorgeB]

10 hours ago, crazygambit said:

but I want to know if it's safe to mix and match.

Usually it's OK, it will run at the lower speed.

[Vr2Io]

2666Mhz RAM run in 2400Mhz won't have problem. The main problem was how mainboard handling in correct, sometimes it is not easy.

 

When I build Ryzen, 4 sticks was 2400, same spec. but different capacity, I face booting problem and finally need re-order stick location for fixing.

 

When I build Z390, four 3000Mhz stick by two model ( that means have two spec. ), mainboard just run it at 2133Mhz. Finally I need tune BIOS setting ( not timing parameter ）for stable run at 2666Mhz.

 

I would say, different brand / BIOS would got big different result.

Edited April 10, 2019 by Benson