A list of Samsung's upcoming 990 Evo SSDs has been posted online; while the release of the 990 Evo series SSDs is not entirely unexpected, their PCIe lane configuration is both surprising and interesting.

The 990 Evo listing was posted on Samsung's Ukrainian website (discovered by WinFuture). According to it, the drive supports both PCIe 4.0 x4 and PCIe 5.0 x2 connections. According to the specifications, the drive supports read and write speeds of 5000 MB/s and 4200 MB/s, respectively. Compared to the best SSDs, this is nothing special and well within the capabilities of PCIe 4.0 x4 connections, but it is the 990 Evo's hybrid PCIe 5.0 x2 support that caught my attention.

Of course, nothing prevents a PCIe 4.0 x4 drive from being used in a PCIe 5.0 x4 slot, but doing so means that the drive uses four PCIe 5.0 lanes; in the 990 Evo's case, PCIe 5.0 x2 support does not reduce performance performance, but it does expand the possibilities for flexibility. Due to the current chipset configurations, lane implementations, and lack of PCIe 5.0 support in notebooks, this dual support flexibility is not likely to benefit mainstream users at this time, but in the future it would be wise. However, in the future, this dual-support flexibility is a wise thing to do.

Future chipset-derived lanes will transition from Gen 4 to Gen 5 at some point, but motherboards already face cooling and electrical challenges with Gen 4 drives; boards with a full set of Gen 5 slots will be even more expensive than they are today, and the Gen 4 drives will be more expensive than they are today.

There are perhaps two obstacles to the adoption of x2 M.2 SSDs, one of which is motherboard support. Motherboard manufacturers will likely consider hardwired x2 slots to be performance limiting. Okay, a board that supports a single PCIe 5.0 x4 drive from the CPU plus another pair of chipset-derived PCIe 5.0 x4 slots (or four x2 slots) is unlikely to be a limitation for mainstream users. If so, there are add-in cards and workstation solutions.

A second barrier is the way SSDs are advertised: as long as large stickers on the front of SSD packages emphasize sequential read and write speeds, high-performance drives are likely to stick to x4 configurations. Of course, there is more to SSDs than sequential transfers. The drive's IOPS, random performance, and internal transfer performance are equally important, and there should be no difference in performance between a PCIe 4.0 x4 drive and a PCIe 5.0 x2 drive. But will the average buyer understand that?

One high-performance PCIe 5.0 x4 drive connected to the CPU and two or three slow but fast enough x2 drives for secondary storage on an inexpensive motherboard would make me very happy. On the laptop side, the x2 drives would save a little power here and there and lower the temperature a bit, without compromising battery life.

We will probably hear more about the Samsung 990 Evo at CES. Let's hope it's just one of many PCIe 5.0 x2 drives.