Asus Crosshair X870E Extreme Motherboard M.2 RAID 0

[skagjr]

I have a strange anomaly with my M.2 RAID 0 on this motherboard.  From a fresh restart or on first boot I get the expected RAID 0 speeds (using Crystal Disk Mark) of over 20000 MB/s. However, after  several minutes, this speed drops to about half. I have checked and double checked that the M.2 cards and motherboard/components are not overheating (not even close) so I do not expect throttling as a result of component over temps. Once this anomaly occurs, it never recovers until I do a restart. At which point the speeds are immediately back to normal for another few minutes and the anomaly repeats.  I have updated all drivers, firmware, software etc. to no avail.  As an experiment, because the RAID 0 carries the operating system, I decided to do an experiment and moved the operating system to the single M.2 card and set up an M.2 RAID 0 storage drive (with no OS). The same anomaly occurs on the non OS M.2 RAID 0. Finally, I have ensured that any OS power settings that can throttle things back have been disabled and I have the latest BIOS installed. I have tried to force PCI-E 5 in the BIOS (changed from Auto setting) and several other settings in the BIOS, but nothing here has helped the issue either.

My CPU is an AMD Ryzen 9 9950X3D.and I am running Windows 11 Pro's latest version/update. My RAID 0 M.2's are Samsung 9100 Pro's (2 cards at 1TB each).

Additional rig info:  I have 1 M.2 card (Samsung 9100 Pro 4TB) in slot 1 for a storage drive and 2 additional M.2 cards in slots 2 and 3 for the OS/RAID 0.  (Yes I know this reduces my video card to an x8 operation due to lane sharing/switching). 

Is there anyone out there that has successfully set up an M.2 RAID 0 on this motherboard that has seen this issue and can help? Would also be helpful to know if someone has set up a RAID 0 with this board that runs consistently at the expected speed without this anomaly?  Appreciate any help you may have and thank you in advance for your time!

[skagjr]

I wanted to add some additional information to my original post:

I created a WinPE boot USB stick that included the necessary RAID drivers and the CrystalDiskMark app.  When I boot to this USB stick and run CrystakDiskMark, the RAID 0 M.2 drive runs rock solid at  the expected speed. I ran the test repeatedly over 30 minutes with high file size/repetitions and everything ran fine with no speed issues.  I believe that this pretty much lets my BIOS settings and physical hardware items off the hook and points back to my Windows operating  system / settings.  I am still at my wits end on what to try as I have turned off all power saving  features etc that might throttle performance.  I still find it  odd that speeds remain fine for about 5 minutes after initial boot or restart, and then degrades.  Help???????  Thanks.......

[skagjr · Accepted solution]

In case anyone is following this post:  I discovered that Norton 365 was the culprit all along.  Even with disk optimization being off, and all auto scans disabled, the RAID0 drive ran at approximately half its expected speed. The moment I uninstalled the Norton product, the RAID 0 drive was back to full speed. Hmmmmm.........

Anyway - running happily with different virus protection at full RAID 0 drive speed.  Stick a fork in this one.