Abnormally low write speed?

[Firegod]

Hi all

DRAM Calculator for Ryzen v1.7.3 is showing something odd, and I don't know what is quite going on. When I run the MEMbench section.

I have an AMD 5800X in an Asus B550-F Gaming motherboard. BIOS and drivers up-to-date. I am overclocking 32GB (2x16GB) DDR4 3200Mhz Kingston HyperX Predator KHX3200C16D4/16GX (Hynix J-die) memory, currently clocked at 3600Mhz.

(~imgbb~ isn't displaying my uploaded image for some reason so I'll try my best to explain and will attach a screenshot of the timings, when ~imgbb~ is working properly.)

But to summarise the issue, basically, MEMbench shows:

Read speed (GB/s) = 43.6
Write speed (GB/s) = 27.4

I thought, it must be my timings, as that write speed seems low! I've tightened up as much as possible, and I can't get the speed to increase whatsoever. It doesn't seem to matter if I have slack or tight timings, stays pretty much the same. I then thought I'll reset BIOS and load defaults, plumb in just the correct default DDR4-3200 timings and try again. All advanced settings and timings and other BIOS features back on auto.

Read speed (GB/s) = 39.9
Write speed (GB/s) = 26

So I take a big drop in Read speed going back to 3200Mhz but yet the Write speed hardly moves.

Any ideas on this one? Is this a bug?

Thanks for any help and advice!

https://i.~ibb.co~/k8xwbQ6/Memory-Slow-Write-Speed.jpg

 

[GregI]

Half write speed on 1 CCD.

 

[Firegod]

@GregI hah how stupid do I feel. I never knew that, so thank you. I guess the 1 CCD has other advantages which negate the slower write.

Managed to get the image into my post as well for posterity.

Mystery solved.