Unraveling NVMe Performance: Why Is My SSD So Slow in AHCI Mode?

If you’ve recently ventured into the realm of Gen 4 NVMe SSDs, you might have encountered some perplexing performance issues. A reader recently shared their experience with an ASUS ExpertBook equipped with the latest Intel 13th Gen processor. Upon installing Windows 11, they noticed that their primary NVMe SSD was only achieving a read/write speed of around 500MB/s in AHCI mode. This level of performance is shockingly similar to that of standard SATA drives and doesn’t do justice to the capabilities of a Gen 4 NVMe SSD.

However, there’s a twist. When the user switched to RAID mode in their UEFI settings and utilized the Intel Rapid Storage Technology (RST) driver, the SSD performance skyrocketed to over 8000MB/s—right where it should be for a cutting-edge NVMe drive.

So, what’s the explanation behind this significant difference? Here are a few insights:

Understanding AHCI vs. RAID

AHCI (Advanced Host Controller Interface) is a protocol designed for SATA drives, which may not fully leverage the potential speeds of NVMe SSDs. When operating in AHCI mode, the system may not provide the optimal drivers or even the necessary features to unleash the SSD’s true performance. On the contrary, RAID mode with Intel RST is explicitly designed to take full advantage of the advanced capabilities of NVMe drives, facilitating higher data transfer rates.

The Role of Drivers

Another potential factor to consider is driver support. Windows typically provides its generic drivers upon installation, which may not be the most efficient for NVMe devices. In RAID mode, loading the Intel RST driver allows the operating system to communicate more effectively with the SSD, resulting in dramatically improved performance.

Is RAID the Only Solution?

While operating in RAID mode offers enhanced performance, it may not be the only solution for optimal SSD speeds. Users can explore other possibilities, such as obtaining the latest firmware updates or drivers and ensuring that their UEFI settings are configured properly.

Conclusion

Ultimately, if you find your Gen 4 NVMe SSD underperforming in AHCI, switching to RAID mode seems to be the way to go for maximum speed. While it may feel inconvenient to commit to this configuration, the benefits in performance are hard to ignore. So, if you’re facing similar challenges, it might be worth considering a transition to RAID mode for an uninterrupted speed experience