Ryzen 5 3600 Low mem write speed

[Nagasaki]

Hi all,

 

I just upgraded my 1600 to a 3600 and I am in the process of tweaking, overclocking and learning the all the new options in the bios that have popped up.

 

But, I have noticed that my write speeds for my ram are half what they used to be. Read and copy show as they did with the 1600 cpu.

 

I used to get about 43000MB/s write and now its down in the 20's... but wait! there's more! I removed all my overclocking and went back to stock everything but using the XMP profile for 3000Mhz for my ram... and the write speed is now 17000MB/s... its getting worse!

 

I can only assume this is some quirk of the 3600?? 

 

What am I missing here? I saw some mention of 4000Mhz ram causing this issue but my ram is not that fast. 

 

I will contiune to investigate while I await your input.

 

Cheers

 

Specs:

 

Ryzen 5 3600

MSI X370 Gaming Plus

16GB (2x8) Corsair Vengeance RGB 3000Mhz CL15

GTX 1070

Corsair CX750M PSU

[Nena Trinity]

Try to run a memtest86 it will take some hours, if no faults they are not defective.

[Guest]

Im curious how the measurements are being taken as this infotmation has been left out.

[Nagasaki]

Using AIDA64

 

But I have found some reddit posts that indicate that this is infact normal for this chip due to the layout of the CCD/CCX

 

In other news...

 

I have got 4.5Ghz @ 1.35v thus far.. Did I win the silicon lotto?!

 

Still testing for stability.

 

I wanted to use PRIME95 but that thing makes my CPU hit 100c INSTANTLY even at stock speeds!

 

And yes, My cooler is mounted right. I did check that. Using a H100i from Corsair.

[Guest]

When you bench test your memory, the less programs using the memory, the scores should go up.

 

So I imagine that each time you run this, you have various different apps open. Web browser, temp monitoring, other various apps. For consistency, try and run the benmchmark the same way every single time with as little running as possible. If the memory is being read or written to during the bench in any way, that will lower you scores.

 

Some timing adjustments help to bring read or write up faster. Sometimes only read will go faster and sometimes write will go faster. This is all on experimentation. Keep trying different tweaks.

 

Not sure about the CCD interfering with a benchmark because of it's layout or design. Could be true? By why would it only effect AIDA64 benchmarking??

[porina]

1 hour ago, Nagasaki said:

I just upgraded my 1600 to a 3600 and I am in the process of tweaking, overclocking and learning the all the new options in the bios that have popped up.

 

But, I have noticed that my write speeds for my ram are half what they used to be. Read and copy show as they did with the 1600 cpu.

This is an AMD design choice, and was discovered soon after Zen 2 launch when reviewers also noticed this. AMD confirmed it was working as intended. AMD chose to only offer half the bandwidth when transferring data from CCD to IOD, saying this was a balance they had to make to conserve power/resources while minimally impacting most software. What this means is that single CCD Zen2 CPUs essentially can't reach full write speeds to ram, outside of some insane overclock maybe. The two CCD models can reach full bandwidth as each CCD take up half the load.