Samsung Readies 990 EVO SSD: Energy-Efficiency with Dual-Mode PCIe Gen4 x4 and Gen5 x2

Samsung’s launch of the 990 EVO M.2 2280 SSD appears to be imminent, as official product pages with specifications went live in certain regions a few days back before getting pulled down.

The most interesting aspect the 990 EVO is not the claimed speeds, but the fact that it can operate in either Gen 4 or Gen 5 modes with different number of lanes. The recently launched mobile platforms from both AMD and Intel use Gen 4 lanes for the storage subsystem. However, with progress in technology it is inevitable that this will move to Gen 5 in the future. In the meanwhile, thermal constraints in mobile systems may prevent notebook manufacturers from going in for desktop Gen 5 speeds (8 – 14 GBps). An attractive option for such cases would be to move to a two-lane Gen 5 implementation that would help in retaining the same Gen 4 x4 bandwidth capability, but cut down on the BOM cost by reducing the number of pins / lane count on the host side. It appears that Samsung’s 990 EVO is a platform designed with such a scenario in mind.

PCIe PHYs / controllers have backward compatibility, and the 990 EVO’s SSD controller incorporates a 4-lane Gen 5 controller and PHY. During the training phase with the host, both the link bandwidth and lane count can be negotiated. It appears that the SSD is configured to advertise Gen 5 speeds to the host if only two lanes are active.

Samsung appears to be marketing only 1TB and 2TB capacities of the 990 EVO. Based on the product photos online, the models appear to be single-sided units (making them compatible with a wider variety of mobile platforms). The flash packages appear to be 1TB each, and the EVO moniker / advertisement of Host Memory Buffer support / controller package markings in the product photos points to a DRAM-less SSD controller – the Piccolo S4LY022. The quoted performance numbers appear low for a 176L / 236L V-NAND product. TechPowerUp believes that these SSDs are using an updated V6 (133L, termed V6 Prime) with better efficiency and yields compared to the regular V6.

Samsung is also touting much-improved power efficiency, with transfer rates being 2 – 3x per Watt compared to the 970 EVO. The Piccolo controller’s 5nm fabrication process and the V6 Prime’s efficiency improvements have a significant say in that aspect.

Pricing and concrete launch dates for the 990 EVO are not available yet. The delta in specifications for the 1TB and 2TB models will be updated in the table above once the drives are officially announced.

Source: Recent News