Samsung 990 Pro vs WD_BLACK SN850X: Which One to Buy in 2026
The Samsung 990 Pro and WD_BLACK SN850X are two of the most popular PCIe 4.0 NVMe SSDs on the market, and on paper they look nearly identical. Here is where they actually differ, and which one to buy.
Spec for Spec
Both drives use the same interface, the same NAND type, and come with a DRAM cache and a 5-year warranty. Rated read speeds are close enough that neither has a meaningful edge here.
| Spec | Samsung 990 Pro | WD_BLACK SN850X |
|---|---|---|
| Interface | PCIe 4.0 NVMe, M.2 2280 | PCIe 4.0 NVMe, M.2 2280 |
| NAND type | TLC | TLC |
| DRAM cache | Yes | Yes |
| Warranty | 5 years | 5 years |
| Rated read speed | 7,450 MB/s | 7,300 MB/s |
Where They Actually Differ
Strip away the near-identical spec sheet and four real differences are left. These are the ones that should actually drive your decision.
- Capacity ceiling: the SN850X scales up to 8TB. The 990 Pro tops out at 4TB, and that is a real limit on the product line, not just a gap in what a retailer happens to stock.
- Single-sided vs double-sided: the 990 Pro is single-sided at every capacity it comes in, including 4TB. The SN850X is single-sided at 1TB and 2TB, but its 4TB and 8TB versions pack NAND on both sides of the board. That matters for anything with a tight M.2 bay, like handhelds, thin laptops, and some small-form-factor cases, where a double-sided drive may not physically fit.
- Power draw and heat: the 990 Pro pulls less power and runs cooler under load than the SN850X.
- Price: the 990 Pro usually costs more than the SN850X. That premium tends to hold across retailers rather than being a one-off sale price.
Both are also sold with a factory-installed cooler, so that is not a reason to pick one over the other. Just check which version you are buying.
The Take
For most buyers, the SN850X is the one to get. It is the more purpose-built choice for gaming desktops and PS5 upgrades, it is the only one of the two with headroom past 4TB, and it usually costs less.
The 990 Pro earns its premium in two situations. The first is a build where space or power draw is the actual constraint, like a laptop, a small-form-factor build, or a handheld, where its single-sided design at every capacity and its lower power draw are the concrete reasons to pick it. The second is a creative or professional workload chasing the last bit of consistent peak throughput, where the 990 Pro's speed and efficiency edge is worth paying for.
PS5 and Console Use
Both drives are sold in PS5-compatible configurations. For the PS5's tight M.2 bay, buy the heatsink version of whichever drive you pick rather than adding a bulky third-party heatsink on top.
A 150 MB/s gap in rated sequential read speed, 7,450 MB/s vs 7,300 MB/s, is not something you will notice in everyday use. The capacity, single- vs double-sided board, and power differences above are what should actually drive the decision.
Bottom Line
Buy the SN850X by default. Buy the 990 Pro if you are working in a space- or power-constrained build, or if you are a creator who wants the fastest, most efficient PCIe 4.0 drive available and is willing to pay for it.
Is the speed difference between them noticeable?
No. Both drives are close enough in rated sequential speed that the difference will not be noticeable in gaming, everyday use, or most creative workloads.
Which is better for a PS5 upgrade?
The SN850X, mainly because it is the more purpose-built gaming drive and gives you room to go past 4TB if you want it. Either drive works well, so pick whichever heatsink version fits your budget.
Which one runs cooler?
The Samsung 990 Pro. It draws less power and runs cooler than the SN850X.