C-die overclocking

[Alastair]

I have been messing around with my memory the past few days. 

I have 32GB Avexir 3600 cl18 memory. 4x 8GB sticks. They are Samsung C-Dies and are pretty underwhelming to work with. Can't crank the voltages unfortunately as they just fall over. So all I have is 1.35v to work with. I tested 1CR and 2CR AT 3600/1800 with my stock xmp settings and saw NO improvement which I was pretty disappointed by that. I figured going to a 1CR I would see at least a bit of a latency improvement.

 

I have managed to get to 3733MHz with an fCLK of 1866MHz. I had to drop the primaries down to 19-21-21-44 2T. I did at least manage to break even on latency. I was getting ~69-70ns at XMP and am managing about the same but with at least a bit of an improvement in bandwidth. 

 

I also tried going down to 3200 and trying to tighten the sticks a bit. I could do 16-18-18 which is very common for c-die 3200 kits. I couldn't get cas15 to boot. 

 

So any suggestions as where to from here? The thing that I get PARTICULARLY lost on are the secondaries and tertiaries. 

 

Stock xmp (Actually 2CR as GDM enabled)

Spoiler

Stock xmp (Actually 2CR as GDM enabled)

 Stock XMP 1CR GDM Disabled.

Spoiler

 Stock XMP 1CR GDM Disabled.

Spoiler

3733 19-21-21-21-44 2T

 

 

Edited April 3, 2022 by Alastair

[Alastair]

A little more tweaking gets me to 3733MHz at 18-21-21-21-36 2T

[Alastair]

I have managed to get 3800 18-21-21-21-44 2T to boot into windows! 

 

Now any ideas how to stabilise it? Samsung C-die doesn't respond to voltage.  And at 1.35ish I am already at the point where C-die starts to negatively scale. 

I have a wad of options in my BIOS ands have no real clue where to start. Any ideas?

I don't know what various RTT, and CAD bus settings do. What do I do with procODT.  I am busy reading the c-die thread on Hardwareluxx but I still don't have much clue on what I am doing once I have primaries down. I have only ever bothered with primaries in my ddr3 days I never played with the secondary stuff. 

[ArchStanton]

I saw your post in the big thread over at OCN.  As I think you are already aware, I am in no position to provide any guidance in the RAM OC'ing arena.  I can only cheer you on from the sidelines.  I too hope to learn the "mystical arts" without simply copying/pasting the settings of others in, how did you describe it, "willy nilly" fashion .

[Alastair]

I also have a thread on hardwareluxx as that seems to be the most definitive thread on C die accross the interwebs. There are a lot of good results. And people getting great results. But no real guidance on what various settings do and how various setting correlate to one another. 

 

If I can get 3800 cl18 stable I will be really happy! Because it would mean around 54GB/s to 55GB/s and 65ns which I will be really chuffed. Not B-die speeds but still respectable for RYZEN

2 hours ago, ArchStanton said:

I saw your post in the big thread over at OCN.  As I think you are already aware, I am in no position to provide any guidance in the RAM OC'ing arena.  I can only cheer you on from the sidelines.  I too hope to learn the "mystical arts" without simply copying/pasting the settings of others in, how did you describe it, "willy nilly" fashion .

 

[The Pook]

8 hours ago, Alastair said:

And at 1.35ish I am already at the point where C-die starts to negatively scale. 

 

...have you tested for yourself? The 32x2 kit of Sammy C-Die in my server is just a cheap 64GB kit but even it scales up to around 1.45v. 

 

best it can do is 3400 16-20-20-36 1T 1.43v, at identical timings at 1.35v it's unstable. XMP is 3000 16-20-20-38 2T 1.35v. 

 

[Alastair]

1 hour ago, The Pook said:

 

...have you tested for yourself? The 32x2 kit of Sammy C-Die in my server is just a cheap 64GB kit but even it scales up to around 1.45v. 

 

best it can do is 3400 16-20-20-36 1T 1.43v, at identical timings at 1.35v it's unstable. XMP is 3000 16-20-20-38 2T 1.35v. 

 

Yes I have verified this. When I set 1.35V in BIOS I GET around 1.38V as reported by software and SLIGHTLY higher than that according to my DMM. At 1.38v GET my XMP (3600cl18) isn't even stable. At 1.33V SET (1.35V GET) xmp is stable and with it I am currently sitting at a very unstable 3800 cl18 that I now need to figure out how to stabilize. 

 

My first step is I am going to try increasing procODT. And then I will try decreasing the drive strength values (lower resistance as I understand it) Hopefully I might find stability.

[Alastair]

So after tweaking and tinkering and a lot of trial and error for most of this week and the entire weekend. I must say I am rather disappointed with my results. After managing to boot 3800MHz I REALLY thought I might have a chance at stabilizing 3800. But it turns out I can't even get this memory to stabilise at 3666. What can I expect from C-Die I suppose. 

 

I went the route of tightening up my secondaries and tertiaries. I couldn't even get my primaries to budge. 

 

In the end I managed to improve my time in Dram Calculators Membench easy preset from 143 seconds down to 128 seconds. 

Geek3 memory score from about 5500/6700 to 5900/6900.

 

Not much improvement in AIDA. 

 

I am sitting here and seriously considering selling these sticks and buying some OEM B-die kits. Just to see if I can get lucky on some cheap OEM ram.

[Alastair]

Ok this really is the end of the road now I promise. Its stable enough that I can daily this in my gaming rig.  

[ArchStanton]

"The road goes on forever and the party never ends".  You know you'll see a random tweak in some random forum post and think to yourself "Hmm, I should try that" .