BIOS/UEFI Configuration for Optimizing M.2 PCIe NVMe SSDs

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When installing a new M.2 NVMe PCIe SSD, you may see some messaging around configuring to increase speeds of NVMe SSDs, or enabling and disabling shared bandwidth of SATA and NVMe ports. We are not able to assist with this in detail due to variations between applicable systems, but it is not a malfunction. Understanding the concepts behind this and where to seek detailed information will allow you to configure your hardware for optimal performance and avoid actual malfunctions, such as SSDs and hard drives not being detected in a system.


POST.pngPOST message appearing when an NVMe SSD is first installed in an ASUS ROG Maximus IX Formula.Your system may have a PCIe x4 mode which is optimal for NVMe SSD performance. In many systems, M.2 ports can be configured in the BIOS or UEFI to toggle this, speeding up connected NVMe drives by removing bandwidth from other ports (typically disabling them in the process), or limiting their performance to maximize available ports if preferred.


While this could be an automated function, it can also be described in a message appearing when an NVMe-compatible slot is populated, or may be mentioned specifically in your system or motherboard manual so you can familiarize yourself with the feature prior to installing hardware.


Manual.PNGExcerpt of storage controller section of ROG Maximus IX Formula manual, discussing how ports will shut off when higher speed PCIe 3.0 x4 mode is enabled.

To manually make these adjustments, refer to support for your system or motherboard for detailed assistance, or any help or tooltips available in your system's BIOS/UEFI itself.


UEFI.pngM.2 bandwidth configuration in ROG Maximus IX Formula UEFI. Enabling x4 bandwidth will speed up NVMe performance and disable SATA ports 5 and 6, per both the manual and tooltip on this screen.