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Level 7
I was running my board in Intel raid mode and getting 2500MBs on my m.2 drive even though it should have been near 3500MBs but I switched it to AHCI and formatted the drive and reinstalled windows, now it's only getting around 800MBs. I can't figure out what's going on with it. No hardware has been changed or switched around. Literally just a bios change and format and new install of windows 11 pro 64bit. I'm running the below hardware and have attached a couple SS for reference. Any Help is very much appreciated.

  • Intel Core i9-11900K
  • Asus ROG MAXIMUS XII FORMULA ATX LGA1200 Motherboard
  • ADATA XPG SX8200 Pro 2 TB M.2-2280


Level 14
You shouldn't be running it in AHCI mode, that's a SATA thing. It should just be NVMe mode with RAID disabled. It looks like CrystalDiskInfo is showing it running in NVMe mode, so it could just be confusing wording in the BIOS or misunderstanding what the BIOS settings are saying. If it somehow is in AHCI mode, that would certainly cripple performance:

Did you "secure erase" the drive after changing the config and before reinstalling? There's probably an option in the BIOS Tools menu to do that. That resets the drive, and marks all of the cells as empty, similar to TRIM. It can't undo the lifetime data written / wear, but it's as close to a factory reset as you can safely get as an end user.

You could try a quick ReTrim in Administrator PowerShell, see if that improves things.

Optimize-Volume -DriveLetter C -Analyze -ReTrim -Verbose

That's non-destructive and just issues TRIM commands to the drive for all of the NTFS free space. Modern SSDs are supposed to be more tolerant of not being properly trimmed, but it has been known to hurt performance in the past. It's kinda the SSD equivalent of defragging, but very quick and doesn't move huge amounts of data around.

You should install AData's SSD Toolbox, and run their diagnostics on the drive, see if it shows any errors or problems, and check if the drive's firmware needs an update:

Level 7
It's not in AHCI mode, it was for almost a year while I was running a raid on some mechanical drives. At that point it was getting 2500MBs now that I took it out of AHCI and shut off the raid, it's showing in the bios properly as a NVME but I'm only getting the speeds above. I just trimmed the drive again. I did it before to but I did it with your method this time and it's still getting the same speeds.

I also installed Adata's software and it found nothing wrong with it. Firmware and Diagnostics were good.

Level 7
Any other thoughts?

Level 7
I gave one last thing a shot, I completely reset the BIOS and viola the drive magically starts running at full speed again... Weird thing is nothing changed in the setting on the bios it was already set to default. I'm not sure what happened but it had to be something stuck from switching from Intel RST / Optane to AHCI. Just figured I'd post this incase anyone else has this issue.