Today we are taking a look at the WD Blue SN550 1TB SSD. This is a mainstream drive from WD featuring PCIe 3.0 x4 connectivity, a WD designed controller, a DRAMless design, and TLC NAND. This is the first DRAMless SSD that I have evaluated, though STH has looked at least one other in the past.
WD Blue SN550 1TB Overview
The WD Blue 1TB comes in a single-sided M.2 2280 (80mm) form factor.
The PCB for the SN550 1TB is almost barren, sporting only a single NAND package and the controller, which are physically distant from each other on the PCB. Supposedly this separation is to allow for easier thermal management, so we will take a look at the temperatures later on. As noted, there is no DRAM cache; the controller itself contains a small amount of SRAM that is managed by said controller. We will look to our performance benchmarks to see if this arrangement holds up.
Unsurprisingly given the sparse population of the front of the drive, the rear is completely barren. As a consumer drive, there is no power loss protection (PLP.) You can read a bit more about why PLP is important in some server workloads in our piece What is the ZFS ZIL SLOG and what makes a good one. That looks at a specific case but has a few diagrams and an explanation around what goes on with these drives when they do and do not have PLP.
WD Blue SN550 1TB Specs
The WD Blue line of TLC based SSDs ranges from 250GB up to 1TB in size.
Our review unit is the top of the line unit from the WD Blue NVMe line, offering the highest performance and endurance. The advertised performance numbers are very modest though, and not intended to compete at the high end of even other PCIe 3.0 drives. On the other hand, the 5-year warranty and endurance numbers are both good.
CrystalDiskInfo can give us some basic information about the SSD, and confirms we are operating at PCIe 3.0 x4 speeds using NVMe 1.4.
Test System Configuration
We are using the following configuration for this test:
- Motherboard: ASUS PRIME X570-P
- CPU: AMD Ryzen 5 3600 (6C/12T)
- RAM: 2x 16GB DDR4-3200 UDIMMs
Our testing uses the WD Blue SN550 1TB as the boot drive for the system, installed in the M.2_1 slot on the motherboard. The drive is filled to 85% capacity with data and then some is deleted, leaving around 60% used space on the volume.
Next, we are going to get into our performance testing.