SSDs with a DRAM Cache

What the DRAM cache actually does

An SSD keeps a map of where every piece of data physically lives in the NAND — the flash translation layer, about 1 MB of map per gigabyte of capacity. A drive with DRAM holds that whole map in fast memory. A DRAM-less drive keeps it in the NAND itself and borrows a small slice of your PC’s RAM (Host Memory Buffer, usually 32–64 MB) to cache the part it is using right now.

That is not a cache for your files; it is a cache for the map. So DRAM makes no difference to a sequential benchmark on an empty drive, and a lot of difference once the drive is full, fragmented, or being hammered with random reads and writes across its whole capacity — exactly the state a drive reaches after a year of use.

When DRAM matters, and when it does not

• Matters: a boot drive you will fill past 70%; a drive for large game libraries that are patched often; video editing, databases, VMs, anything with sustained mixed random I/O; any drive that will live in a system for five years.
• Matters less: a secondary games drive that is mostly read; a PS5 expansion drive (the console never sustains the workload); a laptop where battery life and heat outrank peak performance — DRAM-less drives draw less power.
• Does not matter: sequential copies of big files. There the limiting factor is the SLC write cache and the NAND type (TLC vs QLC), not DRAM.

The honest summary: in 2026 a good DRAM-less TLC drive (WD SN7100, Samsung 990 Evo Plus) is fine for most people. A DRAM-less QLC drive (Kingston NV3, Crucial P310, Lexar NQ780) is where the compromises stack up — it is the combination you should avoid for a primary drive.

NVMe SSDs with a DRAM cache

22 new NVMe drives in our comparison have on-board DRAM, per the manufacturers’ data sheets. All are TLC drives with five-year warranties.

DRAM-less NVMe SSDs (HMB)

23 new NVMe drives rely on Host Memory Buffer instead. The TLC models among them are good value; the QLC models are the ones to treat as secondary storage.

SATA SSDs: DRAM is the dividing line

On SATA the gap is wider, because there is no HMB — a DRAM-less SATA drive has nowhere to put its map except the NAND. The Samsung 870 Evo and Crucial MX500 have DRAM and stay consistent when full; the Kingston A400, Crucial BX500, WD Blue SA510 and TeamGroup QX do not, and can drop to tens of MB/s on sustained writes. For a 2.5-inch upgrade in an older laptop or desktop, the 870 Evo or MX500 is worth the small premium. Full list: SATA SSDs.

How to check whether a drive has DRAM

Look for a separate memory chip next to the controller on a product photo, search the data sheet for “DRAM”, “LPDDR4” or “HMB”, or check the model against the tables above. Brand names are not a guide: Samsung sells the 990 Pro (DRAM) and the 990 Evo Plus (DRAM-less) under nearly the same name, and WD’s SN850X has DRAM while the SN7100 does not.