Question Why do Ryzen CPUs not support fast memory?

[TYPICALHUMAN]

Why high end CPUs like ryzen 7 5800x3d support slow RAM up to 3200 MHz? What's the point of buying fast memory if one use Ryzen? I've read specification of some Ryzen 5 and 7 CPUs and none of them can't support more than 3200 MHz frequency.

 

[jeremyj_83]

Why high end CPUs like ryzen 7 5800x3d support slow RAM up to 3200 MHz? What's the point of buying fast memory if one use Ryzen? I've read specification of some Ryzen 5 and 7 CPUs and none of them can't support more than 3200 MHz frequency.

Even the i9-13900k doesn't support DDR4 above 3200MHz so it isn't just an AMD thing. Now that doesn't mean that you cannot use 3600MHz DDR4 in an AMD system. In reality the 3200MHz is just AMD saying that they GUARANTEE that and of the 3000, 4000, and 5000 chips will work out of the box with RAM at that speed. If you go beyond that you are doing RAM overclocking and that isn't guaranteed. However, since the Zen 2 (3000) series, you have basically been guaranteed that 3600MHz RAM will work for AMD chips in 1 DIMM per channel.

 

[Kona45primo]

The x3d chips do not really need fast memory, it doesn't scale like a non x3d AM4 CPU.The extra v cache makes up for slow ram.

That being said they can potentially reach speeds just as fast as any other 5xxx series CPU. They state 3200mhz max as well but can usually do 3600-3800 but of course not guaranteed and a good Samsung B-die usually works more often than a higher timing non b die version.

 

[hotaru.hino]

The CPU is designed around a certain memory speed, and DDR4-3200 is the fastest, if not closet to it, that the JEDEC standard specifies. Anything faster and it's up in the air whether or not it'll work properly since it's not part of the standard.

So rather than officially support or design around something that's not in the spec, design it around the fastest the spec allows, but allow the use of (but not necessarily support) faster memory if someone really wants it. AMD can only guarantee based around what the spec says.