E1.S SSD Buying Guide: Size by Variant, Connector and UK Prices

E1.S SSD form factor: the dimensions differ by variant

There is no single size to quote for E1.S. Width and length vary by variant first, bare board or enclosure, so we print them by source and say which each one describes:

So an enclosure variant measures 33.75 x 118.75 mm and a bare board about 31.5 x 111.5 mm. Micron's Table 10, headed maximum dimensions, gives those figures per SFF-TA-1006 Rev. 1.4, and its Figures 4 to 6 agree. The maker gap left is Samsung's 33.6 mm width, plus rounding. One discrepancy sits on Micron's own sheet: its features box prints 31.5 x 111.49 mm for all three heights. We have read SFF-TA-1006 only as these documents quote it: Micron at Rev. 1.4, the white paper at Rev. 1.5, which SNIA's 2024 slides date to August 2021. So use the sheet for the exact part number and read it against your server's own bay.

E1.S variants: 5.9, 9.5, 15 and 25 mm are different purchases

A 2022 SNIA and Flash Memory Summit deck describes three enclosure designs for different airflow targets and density needs, at 9.5 mm, 15 mm and 25 mm, plus one enclosure-less design for space constrained or custom applications. The same deck lists standardised widths of 5.9, 8, 9.5, 15 and 25 mm. The KIOXIA, Meta and Microsoft white paper sets out the three enclosures, and Micron's 7450 sheet has the 5.9 mm height:

• 5.9 mm: Micron's bare-board 7450 variant. It is not in the white paper's table.
• 9.5 mm: symmetric enclosure, 20 W sustained. Recommended for 1U edge servers, typically 6 to 12 drives, and named as a U.2 and M.2 replacement.
• 15 mm: asymmetric enclosure, 25 W or more. Recommended for 1U rack servers, typically 2 to 32 drives, and named as a U.2 and M.2 replacement for boot and primary storage.
• 25 mm: asymmetric enclosure, 25 W or more. Recommended for 1U, 2U and larger rack servers, typically 36 to 64 drives, and named as a mainstream U.2 replacement.

Power is part of the choice as well as height. The white paper says 25 W is required to saturate a PCIe 4.0 x4 link, and that the 9.5 mm enclosure scales up to 20 W. SNIA's 2024 slides show a PCIe 5.0 E1.S at 25 W. On that reasoning a 9.5 mm drive and a 25 mm drive are not simply the same product in two cases, so ask for the sustained power of the part as well as its height. Micron's brief describes its heights as options to balance density and airflow.

E1.S SSD connector and hot-plug

SNIA's 2018 overview says EDSFF drives share one connector, SFF-TA-1002, along with the same NVMe protocol and PCIe interface, and it gives U.2 as formerly SFF-8639. Its 2024 slides list that EDSFF connector's specification at revision 1.5 of April 2024, with PCIe 6.0 support. So on SNIA's documents E1.S and U.2 are different connections by name, and we have read no document on carrying one in the other's bay. Samsung's form-factor table prints SFF-8639 under U.2 and leaves the E1.S cell blank, so it names no E1.S connector.

Serviceability is a stated aim. The KIOXIA, Meta and Microsoft white paper lists hot-swapping drives without powering down the whole server, SNIA's 2022 slide lists hot-plug support and its 2024 slide calls E1.S hot plug. Samsung's table marks E1.S as supporting hot-swap and dual-port. The white paper says two LEDs on the front face are mandatory on every variant: a green status LED and an amber fault and locate LED driven by the host. Whether your server's bay and software make use of those features is for its documents to say.

E1.S SSD vs M.2: the same job at different limits

SNIA's 2024 slides sum up the position as higher capacity than M.2 and the same performance as U.2. Another of those slides, in a workstation context, says M.2 is not suitable for higher-capacity Gen 5 drives. The white paper says a typical M.2 SSD is usually limited at 8.25 W. All of these come from people promoting the newer form factor, so read them as the case for E1.S and not as a test result.

E1.S SSD 4TB and 16TB: what the sheets list

The nearest thing to a 4TB E1.S SSD on these sheets is 3.84 TB. That size appears on the white paper's expected list and as 3840GB on Micron's 7450 PRO E1.S, whose full list runs 960GB, 1920GB, 3840GB and 7680GB. The 7450 MAX E1.S runs 800GB, 1600GB, 3200GB and 6400GB.

A 16TB E1.S SSD is less certain. The July 2023 white paper lists expected capacities up to 15.36 TB, and Samsung's table gives a 16TB ceiling for the form factor. But the E1.S models in the sheets we hold stop at 7.68 TB: Samsung's PM9A3, Micron's 7450 PRO and Kioxia's XD7P, which Kioxia lists from 1,920 GB to 7,680 GB at 1 DWPD. A ceiling is not a product, so a 15.36 TB row, if one appears, needs its own sheet. Micron states full power-loss protection for the 7450 series, including E1.S.

Where E1.S goes: servers, NAS and the OEM route

E1.S comes from the large-scale end of the market. The white paper says leading hyperscalers prefer E1.S designs on new and upcoming platforms, and quotes a TrendFocus projection of March 2023 in which E1.S grows from 7.2% of PCIe exabytes in 2022 to 25.9% in 2027. That is a projection, not a measurement, and it says nothing about buying one drive. Samsung's white paper says its E1.S versions are provided to contracted and selected OEM companies, and Kioxia names its XD7P as a data centre line. Initial E1.S SSDs were PCIe 4.0, the white paper adds, while EDSFF drives are designed for PCIe 5.0 and 6.0.

For an E1.S SSD in a NAS, we have not found a NAS maker's document listing E1.S drive support, so we name no NAS. The practical test for any host, server or NAS, is whether its own documents list E1.S and which height.

E1.S SSD price on Amazon.co.uk

The table holds no listings right now. Lowest per TB: -. The table fills from any Amazon.co.uk listing recorded as an NVMe drive with an E1.S form factor, priced in pounds sterling inc VAT. An empty table or a dash means no match at the time shown at the top of the page. It is a statement about our matches, not about whether E1.S drives exist.

E3.S drives are left out on purpose, because they are a separate form factor. SNIA's 2018 overview lists E3 under its own specification, SFF-TA-1008, at (104.9/142.2) x 78 mm, and any E3.S row in our catalogue appears on enterprise NVMe SSDs.

How to choose an E1.S SSD

• Start with the host. Its documents must list E1.S and the height it takes: 9.5 mm, 15 mm and 25 mm are aimed at different servers.
• Match power to the slot. The white paper gives 20 W sustained on 9.5 mm and 25 W or more on 15 mm and 25 mm.
• Read width and length from the sheet for the part, as they vary by variant.
• Read the PCIe generation from the sheet, since E1.S covers more than one.
• Choose capacity from the model's sheet, not the form-factor ceiling.
• Confirm endurance and power loss protection for the part, then read the Condition column and the seller's wording on Amazon.co.uk before you press Buy on Amazon.