Kioxia PCI Express SSD will have speeds up to 14 000 MB/s

Kioxia is already previewing PCIe Gen5 SSDs, up to 14,000 MB/s sequential transfer rates

PCIe 4.0 NVMe SSDs have been on the market for more than 2 years, and the newer ones are even able utilize most of its potential. But PCI Express 5.0 will soon be introduced by Intel Alder Lake processors, though only for GPUs for now (×16 slot). But SSD manufacturers are already preparing PCIe 5.0 storage. Kioxia (formerly Toshiba) has shown a prototype NVMe SSD that uses PCI Express 5.0 and can already get speeds up to 14 GB/s.

This preview of what’s to come in the future—but not yet with Alder Lake and the Z690 platform, where only PCIe 4.0×4 slots will still be reserved for SSDs—was shown during China Flash Memory Summit. It doesn’t have a name yet and currently is just a prototype. But it promises very nice performance. The “Gen5 Prototype” achieves a sequential read speed of 14,000 MB/s, which would largely exhaust the potential of the PCI Express 5.0×4 interface. Sequential write is “only” 7,000 MB/s, but it is possible that it can be improved with further tuning and possibly later also by the usage of newer generations of NAND chips.

The drive is also expected to have better IOPS performance (random read up to 2,500,000 IOPS) and an improved performance per watt ratio. But even latency is supposed to be improved with this future SSD, from 90 μs to 70 μs for reads and from 20 to 10 μs when writing. However, this is probably not so much a benefit of the new interface as it is an improvement in the controller and NAND Flash memory that will be used. This means that similar advances in this direction could already happen in PCIe 4.0 SSDs from Kioxia or other companies that would be using such improved NAND chips.

But keep in mind that we’re probably talking about SSDs not intended for desktops or laptops, but SSDs for servers. The comparison you can see in the slides is against the Kioxia CM6, which is a server drive with a U.2 interface.

Kioxia PCIe 5.0 SSD prototype presentation (Zdroj: 刘于苇/Weixin)

This makes sense because, as we said, there initially won’t be market opportunity for M.2 SSDs with PCIe Express 5.0×4 connectivity on Intel’s desktop platforms (and even on the AMD AM5 socket, which will also only have PCIe 4.0) just yet. But servers should be able to use PCIe 5.0 storage as early as next year with Intel Xeon “Sapphire Rapids” and AMD Epyc 7004 “Genoa” processors (and also IBM Power10, by the way). These processors will have generous amount of PCI Express 5.0 lanes, and the issue that PCIe 5.0 lines employed for SSD steal away connectivity from the ×16 slot for graphics on the desktop platforms (Intel LGA 1700), simply does not exist in servers.

However, we will probably see PCI Express 5.0-based SSDs in the desktop too, probably again in the M.2 module form factor. Server SSDs that are being developed by Kioxia are supposed to use up to 16-channel controllers and it is possible that the 2.5 million IOPS were measured with such a controller. However, it is likely that SSDs for PCs will continue to rely at controllers with 8-channel setup as maximum. Nevertheless we should eventually get to 14-15 GB/s speeds with such controllers as well. However, it is not yet clear when PCIe 5.0 ×4 capability will appear in M.2 slots of PC platforms, as no plan to deploy this type of SSD has been seen on roadmaps or in leaked documents.

Source: Tom’s Hardware

English translation and edit by Jozef Dudáš, original text by Jan Olšan, editor for

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