Odd memory timing issue on Ryzen

[Jito463]

So, for my new Ryzen 1800x build, I went with Corsair 2 x 8GB DDR4 300MHz RAM (CMK16GX4M2B3000C15W).  So far, I haven't been able to get it stable at 2933 (sometimes it will POST, other times it gets stuck and resets the RAM).  However, I'm not terribly concerned about that, as I'm hoping a future BIOS update will fix it.  My specs are in my profile, but I'm running the Gigabyte GA-AX370-Gaming K7 with the F3b BIOS (latest official version).  Here's the odd part.

 

I've got it running stable at 2666MHz, which is fine for now.  I manually set the voltage to 1.35 and the clock multiplier to 26.66.  I then set the timings to 15-15-15-15-36 for both channels A & B (even though I'm only running 2 sticks).  This works and everything is completely stable, however I'm getting conflicting information from Windows.  When I run the CPU-Z version from Gigabyte, it tells me my RAM is running at 16-15-15-15-36.  I've attached pictures of the BIOS settings, as well as a screenshot of the CPU-Z report.

 

I'm not so much concerned about the slower CAS timing (though I would like to fix it), I'm more interested in why I'm getting conflicting data.  Any thoughts?

 

 

 

 

 

[WereCat]

You can check timings in Aida64 as well. Try if just CPUZ isn't bugged.

[Evanair]

Anything above C14 will round up the CL to the nearest even number. 15 becomes 16, 17 to 18, etc etc

[Jito463]

1 hour ago, WereCat said:

You can check timings in Aida64 as well. Try if just CPUZ isn't bugged.

Aida64 is reporting the same timings.

10 minutes ago, Evanair said:

Anything above C14 will round up the CL to the nearest even number. 15 becomes 16, 17 to 18, etc etc

Are you saying the motherboard does this, or Windows?  I've never heard this before.  Where are you getting this information from?

[Evanair]

It's Ryzen chipset itself. It's not something you can fix because that's exactly what it's suppose to do. 

 

"If DRAM Ratio is 2666 or higher TCL will be rounded to nearest even higher number (i.e. TCL=15 → 16)" - Elmor (Asus Motherboard BIOS Tech)  

http://overclocking.guide/asus-rog-crosshair-vi-hero-extreme-overclocking-guide/

[Jito463]

2 hours ago, Evanair said:

It's Ryzen chipset itself. It's not something you can fix because that's exactly what it's suppose to do. 

 

"If DRAM Ratio is 2666 or higher TCL will be rounded to nearest even higher number (i.e. TCL=15 → 16)" - Elmor (Asus Motherboard BIOS Tech)  

http://overclocking.guide/asus-rog-crosshair-vi-hero-extreme-overclocking-guide/

Hmm, interesting.  I guess I need to do some more research.  Maybe I should try pushing my RAM down to CAS 14, then.  Thanks for the link.