Intel's 12th Generation Alder Lake and AMD's Ryzen 7000 (Raphael) processors kicked off the launch of PCIe 5.0 SSDs that deliver blistering storage performance. The new and speedy drives will undoubtedly find a spot on the list of best SSDs but could potentially require a wider M.2 slot.
M.2 SSDs come in different sizes. However, we're accustomed to seeing SSDs arrive in the 2280 form factor in the mainstream market. The first two digits denote width, while the other digits correspond to the length. Therefore, an M.2 2280 drive measures 22 x 80mm. It's the most common form factor that you'll find inside a consumer system.
The M.2 standard always had provisions for wider devices, including 12 mm, 16 mm, 22 mm or 30 mm. We have the established 16 mm, 26 mm, 30 mm, 42 mm, 60 mm, 80 mm and 110 mm sizes for length. Mainstream M.2 SSDs typically stick to 80 mm. You usually don't find 30 mm-wide or 110 mm-long drives outside the enterprise or server market. Nonetheless, many high-end consumer motherboards have at least one M.2 slot that can accommodate drives up to 110 mm, or 22110.
Twitter user Hassan Mujtaba (opens in new tab) shared the alleged specifications for Gigabyte's X670 Aorus Pro AX, X670 Aorus Master, X670 Aorus Xtreme, and X670 Aero D motherboards. They read, in part: "M.2 Thermal Guard III: Ensure 25110 M.2 Gen5 SSD Performance and Stability." It implies that some PCIe 5.0 drives may be 25 mm wide and won't fit into existing motherboards with M.2 slots. However, it isn't a big deal if we look at it objectively since no one in the right mind would pay for a premium PCIe 5.0 SSD and cripple its performance on an older motherboard. Assuming companies designed their M.2 slots with some headroom, we don't see the additional 3 mm being a problem.
TechPowerUp (opens in new tab) has shared the mechanical drawings for the "Type 25110-D8-M" form factor, the standard quoted on Gigabyte's materials. According to the publication, PCI-SIG silently slipped in the 25 mm width at the end of 2020 but didn't divulge it. The description from the document says the "Add-in Card type is primarily intended to support high-power SSD solutions using an optional heatsink." Compared to 22 mm drives, an extra 3 mm may not sound like much. Increasing the PCB wideness by 1.5mm on each side will not likely allow manufacturers to put more NAND chips on it. Besides, we've seen SSDs as large as 8TB, like Sabrent's Rocket Q, that happily fit on a 2280 form factor. However, more landscape could help with heat dissipation and allow vendors to make more robust heatsinks.
We don't expect every PCIe 5.0 SSD to adhere to the 25110 form factor. In Gigabyte's case, the manufacturer probably wanted to future-proof its X670 motherboards for 25110 drives. Conventional 2280 SSDs should still fit the wider M.2 slots without problems. Furthermore, Intel 600-series motherboards with PCIe 5.0 support have been shipping for months now with only M.2 2280 and 22110 slots.
Apacer and Zadak have already announced their PCIe 5.0 SSDs with impressive sequential read and write speeds up to 13,000 MBps and 12,000 MBps, respectively. Unfortunately, the vendors didn't specify whether they were standard 22 mm-wide drives. It'll be interesting to see which brands jump on the 25 mm bandwagon in the upcoming and whether the actual increase in width brings any benefits.