WIndows 10 non-RAID SSD install but RAID Mode in BIOS Question

mikeynavy1976

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Feb 14, 2007
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I've read different answers to this online, including in some threads on Tom's Hardware, although some of the information may or may not be outdated. Hopefully, someone can clear a few things on the subject up for me:

- Both my desktop (Samsung 850 Evo on Asus Prime Z270-A) and Dell XPS 13 9350 were pre-set in RAID Mode in the BIOS when Windows 10 was installed. I'm not sure why...especially the laptop.
- On both the Storage Controller is recent Intel Rapid Storage Technology driver.
- Samsung Magician installed on Desktop and while it shows AHCI Mode as "off" it still picks up the drive data (SMART), firmware check, etc.

Am I losing any performance or features (e.g. firmware update capability, boot speed, transfer speed, etc.) because Windows was installed in RAID Mode with single SSDs? I've read that it shouldn't be the case (e.g. RAID Mode includes AHCI features) but most comments were inconclusive.

If so, I've read about different methods for switching from RAID Mode to AHCI without having to reinstall Windows...however, some of them have comments where people rendered their machines unbootable. Some of that information may be outdated, however. Is there a "safe" way to change from RAID Mode to AHCI...if that is the recommendation?

Thanks in advance.
 
Solution
Not an issue. You will get the same performance and features with RAID on in the bios as long as the drive is actually not in a RAID array.

While I have made a lot of SATA mode bios changes (usually IDE to SATA or SATA to RAID), I would not bother with a RAID to AHCI change as it will not change performance or drive capability and if not done correctly can make your machine unbootable if you don't have some tools handy to fix the issues.

RealBeast

Titan
Moderator
Not an issue. You will get the same performance and features with RAID on in the bios as long as the drive is actually not in a RAID array.

While I have made a lot of SATA mode bios changes (usually IDE to SATA or SATA to RAID), I would not bother with a RAID to AHCI change as it will not change performance or drive capability and if not done correctly can make your machine unbootable if you don't have some tools handy to fix the issues.
 
Solution

stdragon

Admirable
Benchmarks have shown that, yes, AHCI does perform better for a single attached SSD than one in Intel RAID (as a JBOD mode effectively). I'm guessing this has to do with queue depth (NCQ) being more limited or non-existent with Intel RAID mode, but not sure.

Good news - you can change over to AHCI mode without reinstalling the OS. But be sure to make the required registry changes first. Otherwise, if you go an change to AHCI mode, it will throw a BSOD upon boot.

https://www.tenforums.com/tutorials/22631-enable-ahci-windows-8-windows-10-after-installation.html
 

mikeynavy1976

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Feb 14, 2007
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Well...I just changed my laptop from RAID to AHCI using the "safe boot" method. Everything seems to be operating alright. I did have to install the IDE/ATAP controller for my CPU (Intel AHCI Controller driver) and installed the Samsung NVMe driver under storage controllers. I don't notice any performance difference when logged in and using Windows, but the machine does seem to boot a little faster. Will decide if it's worth it to do on the desktop.