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NVMe SSDs

Samsung SSD 990 1 TB, a random write figure and a three-year term vs SanDisk WD_Black SN7100 1 TB, two rates and no slot dimension

The faster pair of numbers, or the page that says what fits and how long it is covered?

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Both of these are 1 TB Gen 4 drives quoting figures in the seven-thousands, and the pages behind them are not doing the same work. The Samsung SSD 990 writes its interface out in full, adds a random write figure and states three years. The SanDisk WD_Black SN7100 is quicker on both sequential rates and never names the form factor, the lane count or a term — on a drive it sells for desktops, laptops and handheld consoles alike.

Samsung SSD 990 1 TB internal M.2 NVMe drive on PCIe 4.0 with four lanes

Samsung SSD 990 1 TB, a random write figure and a three-year term

Wins 5 of 12

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≈ £162 / 172 €

SanDisk WD_Black SN7100 1 TB NVMe solid-state drive on PCIe Gen 4

SanDisk WD_Black SN7100 1 TB, two rates and no slot dimension

Wins 2 of 12

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≈ $188 / £170 / 159 €

Line by line

Compared on SSD 990 1 TB, a random write figure and a three-year term WD_Black SN7100 1 TB, two rates and no slot dimension
Capacity 1 TB, in the title, the first bullet and the box list 1 TB, in the title and in two bullets that are the same sentence twice
Form factor code Not published — M.2 is named, no length code follows Not published — neither a length code nor the M.2 form itself appears
PCIe generation PCIe 4.0, with compatibility stated for 4.0 and 3.0 alike PCIe Gen4, named beside the memory type
Lane count Four — the title writes PCIe 4.0 ×4, the full interface designation Not published — the generation is given twice and never followed by a lane figure
Stated sequential read figure Up to 7150 MB/s Up to 7250 MB/s
Stated sequential write figure Up to 6450 MB/s Up to 6900 MB/s
Stated random IOPS 1,100,000 IOPS, random write; no random read figure beside it Not published
TBW rating Not published, on a page that does publish a term in years Not published — durability appears as an adjective where a volume would go
Stated MTBF Not published Not published
Warranty length Three years, limited, from the maker Not published — no term of any length appears
DRAM cache Not published — neither a memory chip nor a host memory arrangement is named Not published — the flash that stores files is named, which answers a different question
Heatsink Not published — fitting and fastening are described with no thermal part mentioned Not published — the title puts energy efficiency where a cooling arrangement would be

A tick means one listing published something the other did not, or published a better figure. It does not mean the product is better, and the column is not a score out of anything: a maker who says less loses lines here without losing a comparison. The two verdicts below are where the page is settled.

Which one, for whom

Buy the Samsung SSD 990 1 TB, a random write figure and a three-year term

The SSD 990 loses both speed rows by a hundred and four hundred and fifty megabytes a second, and wins the comparison on everything a buyer has to know before ordering. It is the only one of the two to print the lane count, so the interface designation is complete; the only one to give a figure in IOPS, even if that figure covers writing alone; and the only one to state a term. Three years is short for this shelf, but it is three years more than the alternative states.

Buy the SanDisk WD_Black SN7100 1 TB, two rates and no slot dimension

The SN7100 is the faster drive on the page: 7250 MB/s reading, 6900 MB/s writing, both ahead of its rival. Everything else is missing. No form factor, so nothing says which slot it fits; no lane count, so half the interface designation is absent; no term, no total written, no figure in hours. If the machine is known to take a 2280 card and the drive is going in for speed, that may be enough. If anything about the fit is uncertain, the page will not settle it.

The questions that come up before an order

Why does the missing form factor cost the SanDisk a row it seems to tie on?

Because the two pages are silent in different ways. Samsung names M.2 and omits only the length code; SanDisk names neither. A buyer reading the Samsung page knows the slot type and has one thing left to check. A buyer reading the SanDisk page has two, on a drive its own title offers for three quite different kinds of machine.

Is 1,100,000 IOPS a general performance figure?

No — the bullet names it as random write, and no random read figure appears beside it. Random reading and random writing are separate measurements, and a page that publishes one has published one. This comparison records the figure exactly as the listing frames it.

The full reviews

  • NVMe SSDs

    Samsung SSD 990 1 TB, a random write figure and a three-year term

    1 TB · M.2, length not published · PCIe 4.0 ×4 · up to 7150 MB/s read · up to 6450 MB/s write · 1,100,000 IOPS random write · three-year limited warranty · no TBW, no MTBF

    A one-terabyte Gen 4 drive that publishes a random write figure in IOPS and a three-year term, and that never prints the length code an M.2 slot will physically test.

    Best for: A board whose M.2 slot is already known to take the common length, where a published random write figure and a named update route are worth more than a longer term.

    ≈ £162 / 172 €

    Check price on Amazon Read the review
  • NVMe SSDs

    SanDisk WD_Black SN7100 1 TB, two rates and no slot dimension

    1 TB · PCIe Gen 4 · up to 7250 MB/s read · up to 6900 MB/s write · three-level cell memory named · no form factor, no lane count · no TBW, no MTBF, no warranty

    A one-terabyte Gen 4 drive that publishes both sequential figures and the memory type, never names a form factor or a lane count, and ends its title in the middle of a phrase.

    Best for: A machine whose slot is already known to take the common Gen 4 stick, where the pair of sequential figures is the requirement and the fit has been settled elsewhere.

    ≈ $188 / £170 / 159 €

    Check price on Amazon Read the review

Every price named in a summary was read on the date that review carries. What a shop asks today is shown beside the product, and it moves.