ASUS Hyper M.2 X16 Gen 4 Card: four NVMe SSDs in one PCIe slot

The ASUS Hyper M.2 X16 Gen 4 is an expansion card that plugs into a PCIe slot and carries up to four NVMe M.2 solid-state drives. It suits anyone who has run out of M.2 slots on their motherboard, or who wants a fast multi-drive array for work or storage. ASUS designed it for RAID setups on supported AMD and Intel platforms.

What the card does

Most motherboards offer only a few M.2 slots. This card adds four more by using a full-length PCIe x16 connection and dividing it among the drives. ASUS rates the card at up to 256 Gbps of combined transfer speed, which is the bandwidth of a PCIe 4.0 x16 link shared across the four drives.

The card accepts M.2 drives in 2242, 2260, 2280 and 22110 lengths. These numbers are width and length in millimetres, so a 2280 drive is 22 mm wide and 80 mm long. The 22110 size is longer and is mostly seen on enterprise-style drives.

PCIe 4.0 and what it means for speed

PCIe 4.0 doubles the per-lane bandwidth of PCIe 3.0. Four lanes of PCIe 4.0 are typically enough for a fast NVMe drive to reach several gigabytes per second. Since each drive on this card gets its own set of four lanes, all four can run at full speed together, as long as the motherboard can supply the lanes.

ASUS says the card is built on server-grade, low-loss PCB material to keep the signal clean at these speeds. It also says it supports drives drawing up to 14W, which covers many high-end drives that run warm under load.

Cooling

Fast SSDs slow themselves down when they overheat, a behaviour called throttling. The card has a heatsink and an integrated blower-style fan, which ASUS says prevents M.2 throttling. A blower pulls air across the drives and exhausts it, so a fan will be audible in a quiet system. Check ASUS's fan control notes for how the speed is managed.

Platform support and RAID

ASUS names three targets: AMD 3rd-generation Ryzen Threadripper on the sTRX40 platform, AMD AM4 systems, and Intel VROC NVMe RAID. The card also works in x8 slots, according to the listing, but with fewer lanes available the drives will have to share bandwidth, so expect each drive to have less than a full link.

A key point is bifurcation. The motherboard must be able to split an x16 slot into four x4 links, and this is set in the BIOS. Without that option, only one drive will typically show up. The motherboard manual should say whether and how this is supported.

Who it suits

• People who want more NVMe capacity than their motherboard offers.
• Anyone building a RAID array of NVMe drives for editing, databases or virtual machines.
• Workstation builders with a spare x16 slot who are not using it for a graphics card.

What to check before you buy

• Bifurcation support: confirm your motherboard and BIOS can split an x16 slot into x4/x4/x4/x4.
• A free slot: the card uses a full-length slot and sits next to your graphics card, so check clearance and airflow.
• Available lanes: adding drives to a slot may reduce lanes elsewhere on some boards.
• Drive sizes and power: make sure your drives are among the supported lengths and within the 14W limit.
• Noise: the blower fan adds sound, and you should decide whether that matters in your setup.
• Operating system and RAID software: check how your chosen RAID mode is configured on your platform.

The short version

• A PCIe 4.0 x16 card that holds four NVMe M.2 drives (2242, 2260, 2280 or 22110).
• ASUS rates it at up to 256 Gbps and supports drives up to 14W.
• Heatsink and blower fan to limit throttling.
• Made for sTRX40, AM4 and Intel VROC NVMe RAID.
• Needs a motherboard that supports x16 bifurcation.

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