Question CL15 Ram is listing as CL16, but xmp properly set it to its intended CL15 in bios.

[Bradley_]

My system is not allowing the correct RAM latency speed - it’s doing CL16 instead of 15.

Hardware:
Asus b450-f (bios updated)
Ryzen 5 3600
16(2x8)gb ddr4 G.Skill Ripjaws 4, 3000mhz/CL-15-15-15-35

To start, the ram needed xmp on in the bios for it to register above 2k MHz speed - thankfully just one click in the bios and it changed every setting to the correct given specs listed on the ram (plus what I assume is standard for this kit - a boost to 1.35v on dRAM voltage). I left everything else in the bios to auto/stock settings.

When I open CPU-Z, it shows under memory tab that my “CAS# Latency (CL)” is 16 instead of 15. The whole list in cpu-z is:
Memory Tab
(CL) 16.0
(tRCD) 15
(tRP) 15
(tRAS) 35
(tRC) 71
(CR) 1T
==========
SPD tab:
3 JEDEC Colums with lower settings, then 4th column has all the right settings:
XMP-3002
1501mhz
15.0
15
15
35
50
1.35 V

1 week old PC, I just noticed this. Double checked in the BIOS timings, right side column for manual settings input indeed says 15, but to the left it reads cl 16.

Can anyone help me get it to the actual correct CL15?

Thanks!

Btw I ran 4 hrs worth of ‘MemTest’ diagnostic using 12 instances of it checking 1gb to 2gb each, and a couple extra to pick up the crumbs. Task manager showed memory fluctuating from 97-100% the whole time. Many got 500%-800% coverage, others over 1200% coverage. Zero errors.
All drivers/win10 and bios are updated

Thanks again for any help!!

 

[boju]

Ryzen rounds odd CL timing to even numbers, it's normal afaik. Happens to everyone.

 

[Bradley_]

Ryzen rounds odd CL timing to even numbers, it's normal afaik. Happens to everyone.

then why are the other 15’s also not bumped to 16?

With the other timings still holding 15, would it be worth my time swapping this kit out to Ripjaws 5, 3200cl16?
They were both the same price but I picked 3000cl15 because I figured those 15 timings would be more effective than an extra 200mhz (using on a Ryzen 5 3600 cpu)

 

[boju]

Lot of people are reporting the same, only the first timing - CL doesn't accept odd numbers for whatever reason. Those that I've seen their systems is completely fine.

There is absolutely no difference between CL 15 and 16.

Not worth the hassle, don't worry about it and enjoy your system.

 

[boju]

https://www.crucial.com/usa/en/memory-performance-speed-latency

 

[gskill support]

Use a benchmark test or another software to check, it may also be a CPUz reading issue.