Summary
Setting up an SSD isn’t hard, or at least it shouldn’t be. Depending on whether you have a SATA drive, your SSD’s storage controller would be in AHCI mode; for M.2 drives, it would be NVMe. However, there’s another storage controller mode beyond these two options, called RAID mode. The average PC user doesn’t need to worry about RAID since it is useful for networking and servers. Yet, most laptops and OEM builds still come with RAID by default, even though it adds unnecessary overhead and makes your SSD slower than it should be. What RAID mode does on a single-drive setup One drive, zero redundancy, and extra overhead RAID configurations are typically used with multiple drives to make them appear as a single drive. Contrary to popular belief, RAID isn’t used for backup but for redundancy, keeping your computer working even if one drive fails (except RAID 0). Multiple RAID configurations can change how you want the system to operate: RAID 0 splits data across two drives, RAID 1 mirrors data across drives, and RAID 5 splits data across multiple drives, with data still recoverable via distributed parity. You can combine RAID 1 and 0 as well, called RAID 10, while RAID 6 is RAID 5 with double parity, which can survive two failures instead of one. In a single-drive setup, RAID doesn’t provide redundancy but changes the driver configuration required to communicate with Windows. So, instead of talking through the AHCI controller and driver, it routes through the Intel storage controller, then the Intel driver, and then to the SSD itself. It isn’t even a SATA problem — NVMe gets it too Intel’s VMD can enable RAID on NVMe drives too NVMe is the modern communication protocol that uses PCIe to communicate with the system on board instead of SATA connections. So RAID technically shouldn’t work with NVMe because PCIe devices bypass the SATA controllers. However, you can still enable RAID on NVMe drives if they’re routed through Intel’s RST (Rapid Storage Technology), a driver technology that improves storage performance and relies on Intel’s VMD (Volume Management Device), a hardware controller built into Intel CPUs to manage high-speed NVMe drives. So you could have bought a newer laptop recently with an NVMe SSD and still have RAID mode enabled. Why this setting is slowing you down Extra driver hop your SSD doesn’t need For an average PC user, RAID complicates communication between Windows and the SSD since the system has to do additional drive processing, commands, controller tracking, striping, and parity mirroring, ultimately burdening the CPU with these calculations. Some storage software won’t work properly because it fails to recognize the drive behind these Intel drivers and controllers. Otherwise, reinstalling Windows would require the appropriate RST driver to detect the storage drive. Dual-booting with a secondary OS like Linux also becomes a hassle with RST enabled. Intel’s RST also has a history of bugs and failures, and switching to NVMe/AHCI without prep can leave Windows unbootable, sometimes even prompting a reinstallation. Why do manufacturers default to RAID? An intended factory default With desktop PCs, you can configure the setup to your liking, but with OEM builds and laptops, the manufacturer’s default settings take away some of that freedom. For these setups, RAID is mostly enabled by default thanks to Intel’s RST, which enables multi-disk capabilities such as mirroring, caching, or striping. Beyond that, they’ve mostly kept the same factory settings tested across all the laptops being built at the time. Since RST gets validated under RAID, there’s no reason to switch to NVMe or AHCI. Then, laptops with different storage variants are also deployed with all SSDs in RAID setups, where the manufacturer would deploy one master copy across all of these systems using something like RAID 1, which would be left by default. How to check and switch safely to NVMe/AHCI Do it without breaking Windows First, you’d need to check whether your laptop or OEM PC is using a RAID setup rather than AHCI or NVMe. Most mainstream and budget laptops are shipped with RAID enabled, as are some Dell Latitude, ThinkPad, and other HP Intel-based business laptops. Nevertheless, you can check it yourself by going to Device Manager → Expand Storage Controller; if you see something like Intel’s RST or VMD, your system has RAID enabled by default. To disable:
- Enter BIOS by pressing either F2 or Delete.
- Go to Storage → SATA operations → Storage controllers.
- If it says RAID, and you’re switching from a SATA drive, set Safe Boot in Windows first.
- Restart into Safe Mode, enter the BIOS again, and change RAID to AHCI.
- Save and boot into Windows. For NVMe systems, the process is a bit different, and you’ll have to follow this path:
- Go to the BIOS.
- Search for Intel VMD/VMD Controller under the Storage section.
- Disable it.
- Save and boot into Windows. A 5-minute fix that goes a long way Even if RAID is enabled on single-drive setups, no array mode is active, so there’s nothing to lose. Still, this storage controller mode is useless and adds overhead. Switching to AHCI/NVMe without loading the proper driver stack will make your system unbootable, which is why it’s important to boot into Safe Mode so Windows loads the right driver beforehand and can still find the boot drive after the switch.