Ryzen experience - command rate question

[Divideoverflow]

Hello,
I know the new Flare-X and Fortis chips are the AM4 approved series, but unfortunately there wasn't any info about those when I pre-ordered my Ryzen parts, and went for a set that was decently priced at the time with good performance ratings. I've been a long time G.Skill owner, and wanted to get some feedback.

I purchased qty 2, DDR4-3200 16GB chips, model# F4-3200C15-16GTZ, which supports 15-15-15-35. I went with the 16GB chips because I may want to move to 64 GB in the future for my engineering applications, if it ever becomes necessary (right now I'm fine with 32GB).

The best I've been able to do is this:


I've also been able to run at DDR-2400 w/ 14-14-14-33 timings (EDIT: 12-12-12-32), but I was reading that the AM4 platform benefits more from the ram frequency due to the architecture of the CCX linkages running at a fixed ratio speed to the RAM (1:2, I think?).

So the sub timings are not accessible to me yet via the bios (I think they are locked for everyone at this point). Is the XMP rating for these chips based on a 2T command rate? I was wondering if that was part of the issue with achieving faster speeds, as it is hard locked to a 1T rate.

Additionally, would it be better to be at my current 2666 18-18-18-38, 1T, or if I could get to 2933 with similar timings but a 2T rate in the future? I'm unsure of the performance implications of command rate if it means I can jump up a speed range.

Thanks! I still have a rig running 4x4GB of G.Skill DDR3-1600 from 2010, and it is still kicking great :-)

[PeZzy]

What Motherboard are you using? Is the BIOS up to date?

Did you try 2666Mhz with 14-12-12-12-32-1T ?

The forums at overclock.net might be more useful to you as there are people testing various memory there.

For Crosshair 6, there are two beta firmwares, one for 1T and one for 2T. 1T has better performance, while 2T tends to be more stable.

[Divideoverflow]

I took a chance and have the Biostar X370GT7. They've been doing bios updates for memory compatibility, but haven't unlocked subtimings yet. I've got the current bios from 3/14.

The machine won't post at 2666 with a CL less than 18. If I put 17-17-17-XX, it will post with 18-17-17-XX, basically just overriding my choice. If I try CL16, it won't post at all.

I can get it to post at 2933 on warm boots, but it isn't stable, and am unable to cold boot at that speed. Allegedly there is a fix going to go out for the 2933 and higher timings at some point.

I can peek over at overclock.net and see what they've got.

[Divideoverflow]

As an update, I've noticed that the 2400 speed setting runs in 2T command rate, but 2667 only runs in 1T (with no way to try and set the command rate manually, that is just what they show up as). I'm guessing that is why I can get my timings down to 12-12-12-32-2T @ 2400, but am stuck at 18-18-18-38-1T for 2666.

[GSKILL TECH]

Yes, chips are generally rated for 2T.

You can test he different settings to see which performs the best, or which settings is best for your purposes.