Question RAM speed is limited by the CPU or the motherboard ?

[Wing901]

According to Intel webpage, memory speed of i5-7200 is up to DDR4 2133. However, CPU-Z shows that the RAM speed is 2666.

Lenovo ThinkPad E580
i5-7200U
8GB

 

[kanewolf]

According to intel webpage, memory speed of i5 7200 is up to ddr4 2133. However, the cpuz shown that the ram speed is 2666. (Lenovo e580, i5 7200u, 8G)

Anything above 2133 is an "overclock". Not guaranteed to work by Intel. Typically works just fine.

 

[geofelt]

It depends.
Ram speed can be limited by the motherboard.
And/or the processor,
and the ram itself.
Often the supported ram speed is the default the motherboard will boot with.
Later adjustments may allow the motherboard bios to increase the speed to a higher number.

 

[FreeBee101]

It used to be in the North bridge I think. Now, on amd atleast, the northbridge is on the cpu. Not sure on intel.

 

[CountMike]

It used to be in the North bridge I think. Now, on amd atleast, the northbridge is on the cpu. Not sure on intel.

Memory controller is in the CPU for all CPUs. for very long time now. Some like AMD Ryzen have dedicated Chiplet for I/O including RAM.MB may limit RAM frequency because of wrong architecture an BIOS may not have proper settings so you might have to set all/most parameters manually without relaying on JEDEC or XMP.