Although solid-state drives with a PCIe 5.0 x4 host interface have been around for a while, drives that are capable of 14 GB/s sequential read speeds are still expensive. This is largely because the market has been dominated with Phison's PS5026-E26 controller. But this soon may change as Patriot is prepping a particularly interesting product — the Viper PD573 SSD, with a prototype being demonstrated at Computex 2024, that promises to bring together very high performance and a relatively low price.
The Patriot Viper PD573 is based on Maxio Technology's MAP1802 DRAM-less controller (four NAND channels at up to 4800 MT/s, 14.4 GB/s, 3.4M read IOPS, 3.5M write IOPS) designed for inexpensive SSDs and 3D NAND from Yangtze Memory Technologies Co. (YMTC). As for capacities, expect the Viper PD573 to come in 1TB, 2TB, 4TB, and 8TB configurations.
Patriot expects the Viper PD573 drives to hit up to 14,000 MB/s read speed as well as up to 12,000 MB/s write speed, which is a relatively conservative target given the numbers outlined by Maxio itself. The combination of a Maxio controller and YMTC 3D NAND memory is not new to Patriot, so the company is familiar in how to use and tune it, so it can probably achieve its performance targets.
There is a catch about achieving up to 14,000 MB/s sequential read speeds using a controller with four NAND channels. Considering encoding overhead of an ONFi interface (8b/10b encoding, overhead is 20%), to get to 14,000 MB/s, one needs to use 3D NAND with at least 4200 MT/s interface and that memory does not exist yet.
YMTC's existing 3D NAND devices with the Xtacking 3.0 architecture feature an interface of up to 2400 MT/s, which is fast. The company's next-generation Xtacking 4.0 devices could get an even faster interface given YMTC's unique architectural advantage over competitors (peripheral logic and PHY are produced on a different wafer using an optimized process technology, 3D NAND array produced on a separate wafer), but we do not know whether it is going to support a 4200 MT/s interface from the start.
In any case, the MAP1802 is at its early stages, both Maxio and Patriot will spend time optimizing the controller firmware, ready for YMTC's next-generation 3D NAND to enter mass production. Patriot believes that that YMTC will have the memory it needs to build inexpensive PCIe Gen5 x4 SSDs rather sooner than later, so the Viper PD573 could hit the market late in 2024, though this is an optimistic assumption.
