Showing results for 
Search instead for 
Did you mean: 

ROG Crosshair VIII Hero - Mixed Ram Speeds - Need advice

Level 7
I have a query about ram speeds on my motherboard. I have an Asus ROG Crosshair VIII Hero, BIOS version 3801 x64. CPU is a Ryzen 3900x.

I'm running Unraid. After a system crash, I've been advised to clock back my ram by the Unraid team as it's known to cause parity issues with the Unraid system. I was advised to clock it back to 2167Mhz, I presume this was a typo and it should be 2166Mhz so I set it to that frequency.

I have 64GB of ram in this machine. On the BIOS "main" screen it shows Total memory of 64GB & a memory frequency 2666Mhz.

The two packs of ram were bought separately. As in I got 2 x 16 and then another pair a few months later. This is the exact spec of what I bought.

32GB (2x16GB) Corsair DDR4 Vengeance LPX Black, PC4-28800 (3600), Non-ECC Unbuffered, CAS 18-22-22-42, 1.35V

In the BIOS under "Extreme Tweaker" I've left everything to "auto' except I've changed the memory frequency to "DDR4-2666Mhz". The system boots and is stable in Unraid.

My query is when I visit the BIOS and go to "Tool / ASUS SPD Information" the ram speeds are different.

  • Slot A1: 2666Mhz
  • Slot A2: 2133Mhz
  • Slot B1: 2666Mhz
  • Slot B2: 2133Mhz

Why are A2 and B2 running below the set speed? It's bad enough I've had to clock down from 3200Mhz for OS stability but if there is still speed to be gained from slot A2 and B2 I would rather have them running at 2666Mhz.

Can anyone advise? Thanks

Level 7
Hi theÂ*SPD Information is what settings are stored on the ram if you had brought them from the same place at the same time they will likely be the same but if you have ordered them months apart there’s a good chance they are different versions have a look on the ram should say something like version 3.43 if they are different there could be any number of parts different on the ram and might not work well together. You’re ram will be running at the speed you set in the bios.

I understand now, thank you