Can someone help me understand what this means?

[KateB]

I've been looking at motherboards and memory and came across details like this "4 x DIMM, Max. 128GB, DDR5 5200MHz upto 6400MHz (OC)" or supports 7600+(OC)/ 7200(OC)/ 7000(OC)/ 6800(OC)/ 6600(OC)/ 6400(OC)/ 6200(OC)/ 6000(OC)/ 5800(OC)/ 5600(OC)/ 5400(OC)/ 5200/ 5000/ 4800

Now the part I'm confused with is the "5200MHz upto 6400MHz (OC)" or that some frequencies have (OC) and some don't.

I understand that OC probably means overclocked but what does that actually mean in terms of buying and installing ram?

If I wanted to buy some 6000MHz ram would it be a simple plug and play or would I have to adjust some setting, possibly in the bios, or something even harder?

Thank you.

 

[KateB]

Thank you.

I "think" I understand.

So it's not just the motherboard that dictates what ram can be used but also the CPU, and in this case, regardless of how high the board states it will be limited by the CPU, which in your example the 7800X3D, is 5200MHz?

So the safe bet is to go with 5200MHz or take a chance on 6000MHz if it says EXPO?

Did I get that right?

 

[KateB]

Wonderful, got it.

Thank you so much.

 

[KateB]

The motherboard doesn't really matter (like, at all) for the average user buying mainstream memory, but it does if you want to achieve stability at really high speeds.


You will have to enable EXPO (EXtended Profiles for Overclocking) in the BIOS, which as the name implies: this is overclocking.

If you do NOT enable EXPO then your expensive memory will run at the default speed, which is usually just 4800.

The manufacturer of the memory rates their memory to perform at those settings and they will offer their warranty if it fails, but your CPU is only rated to operate at 5200. AMD partly do this to cover themselves because they need to support a wide range of CPUs, some of which have stronger memory controllers than others.

The official spec for Ryzen 7000 series is:
2x sticks, single rank (e.g. 2x8/2x16/2x24GB): 5200
2x sticks, dual rank (e.g. 2x32/2x48GB): 5200
4x sticks, single rank (e.g. 4x16): 3600
4x sticks, dual rank (e.g. 4x32): 3600

(All CPUs have the same spec, but you can find it here:
https://www.amd.com/en/products/processors/desktops/ryzen/7000-series/amd-ryzen-5-7600.html )

As Rob_B said, the chances of 6000 not working are somewhat slim, but it can happen and you can't return your stuff as faulty if it doesn't run stably at this speed.

As always with overclocking, you trade stability (and potentially: reliability) for speed.

Memory overclocking has got so common now that most users don't even consider it overclocking and 99% of benchmarks and reviews published online do not follow the official spec from the CPU manufacturer. Heck, even AMD and Intel often publish their benchmarks with EXPO or XMP enabled.

I'll be getting 32GB - 2x16.

Thank you.

 

[KateB]

As someone who recently switched from Intel to AMD i was initially disappointed that the ram i had on intel board would not run at it's rated speed of 7600mhz, i did get it to boot at 7200mhz but it would not stay like like after a reboot it went back to 4800mhz.

After watching many videos and reading forums i settled on setting the memory to 6000mhz cl30 timings for lower latency.

I think 6000mhz is the sweet spot for AMD 7800X3D.

Good to know, Thank you.