Ryzen RAM Query

aaronjlaw · 23 Apr 2017 at 20:51

Hi all,

I recently posted about needing a new system and I have built my Ryzen 5 rig!

All is well however my RAM frequency has defaulted to 2133mhz although I know my setup can do more.

I have these components:

Corsair Vengeance LPX 16GB (2x8GB) DDR4 PC4-21300C16 2666MHz Dual Channel Kit - (CMK16GX4M2A2666C16)
ASUS PRIME X370-PRO - AMD RYZEN ATX Motherboard

I have updated my Asus board to the latest BIOS but do I need to change voltages and frequencies manually myself as still defaulting to 2133mhz...

Any help appreciated, thanks!

DarkHorizon472 · 23 Apr 2017 at 21:00

For the moment most motherboards struggle to autodetect RAM at the correct settings and boot under ryzen.

The simplest approach is in your BIOS just chose the speed you want and reboot. My 3200 RAM booted at 2133 on auto, while it won't yet run at 3200 it boots normally on 2933 once I chose that speed in the BIOS.

aaronjlaw · 23 Apr 2017 at 21:04

DarkHorizon472 said:
For the moment most motherboards struggle to autodetect RAM at the correct settings and boot under ryzen.

The simplest approach is in your BIOS just chose the speed you want and reboot. My 3200 RAM booted at 2133 on auto, while it won't yet run at 3200 it boots normally on 2933 once I chose that speed in the BIOS.

I changed it pre-BIOS update and it wouldn't boot so I had to clear CMOS.

With the latest BIOS you reckon this is the best approach? I will try it again...

Tomintoul · 30 Apr 2017 at 10:56

Don't know if you sorted this yet, but go into the BIOS, head over to Ai Tweaker change from Auto to DOCP. Next dropdown, set the RAM speed you want to try. Then go down and change your memory voltage from auto to 1.35V

aaronjlaw · 30 Apr 2017 at 13:28

Tomintoul said:
Don't know if you sorted this yet, but go into the BIOS, head over to Ai Tweaker change from Auto to DOCP. Next dropdown, set the RAM speed you want to try. Then go down and change your memory voltage from auto to 1.35V

Thanks, it didn't go into the boot loop but did randomly cut out when using my PC so took it down to 2400Mhz and it seems stable currently...

Monstermunch · 1 May 2017 at 15:50

A lot of people seem to be having issues with Ryzen and Corsair Ram

cimurray · 2 May 2017 at 19:53

aaronjlaw said:
I have updated my Asus board to the latest BIOS but do I need to change voltages and frequencies manually myself as still defaulting to 2133mhz...

I have a very similar set up to you but with the corsair 3200 RAM. Your memory is rated at 1333Mhz which runs clock doubled to give the 2666MHz you are looking for - see Corsair's website http://www.corsair.com/en-gb/vengea...66mhz-c16-memory-kit-black-cmk16gx4m2a2666c16
To get to your speed go into the advanced tab in the BIOS and go to AI Tweaker:
Then select AI Overclock Tuner - set to D.O.C.P.
DOCP - set to D.O.C.P. DDR4 - 2666 16-18-18-35
Memory Frequency - set to DDR4 - 2666MHz

With a bit of luck, and if you are on the most recent BIOS for your motherboard, you will boot straight into your desired setting without any messing around with memory voltages as this kit runs at 1.2 volts out of the packet. You may have to settle for a slightly slower speed if your system will not boot at 2666MHz but that is just an issue with Asus still maturing the BIOS to work with the memory. I have exactly the same issue and am currently running my RAM at 2994 instead of the 3200 rated speed - but it's not the memory that's the problem; it's the BIOS for the motherboard.
Good luck.