E1.S Form Factor

E1.S · 1U short form factor · SFF-TA-1006

SFF-TA-1006 Rev 2.0, dated December 19, 2025, prints Table 7-1 Initial Slot Power Limit(12Vpinit) as 12 W only for the 5.9/8.01 mm column and 25 W only for the 9.5/15/25 mm column. Informative section 7.3 prints no specified maximum sustained power apart from 6.6 A, which at 12 V nominal limits the form factor to 79.2 W and is further limited by the host and device. The power-page footer prints Copyright © 2026 SNIA, which is not that revision date. [ta1006]

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E1.S is the 1U short device form factor of SFF-TA-1006, with thickness-specific 12 W and 25 W initial slot power limits that are not the 79.2 W connector capability.

Read E1.S as one short outline with more than one thickness. SFF-TA-1006 Rev 2.0, dated December 19, 2025, defines a 1U short device that fits vertically in standard 1U rack mounted hosts. Section 3.3 defines 1U as 44.45 mm (1.75 inches). Section 5.1 lists 5.9 mm, 8.01 mm with an optional heat spreader, 9.5 mm with an optional symmetrical enclosure, and 15 mm and 25 mm with an optional asymmetric enclosure. The bare-card table prints A1 5.9 REF, B1 31.5 with tolerance 0.2, and C1 111.49 with tolerance 0.15. The symmetric enclosure table prints device width B4 33.75 with tolerance 0.25 and device length C3 118.75 with tolerance 0.55. Section 5.5 says dimensions not specified in Table 5-4 stay the same as Table 5-3. [ta1006]

Keep the three power prints apart. Table 7-1, Device Power Requirements for a 1U short (E1.S) system implementation, labels Initial Slot Power Limit(12Vpinit) as 12 W for the 5.9/8.01 mm column and 25 W for the 9.5/15/25 mm column, and tells the reader to see SFF-TA-1009 for definitions. The maximum device power capability cell, spanning both thickness columns, prints up to 79.2 W at 12 V, limited by the current capability of SFF-TA-1002. Informative section 7.3 says there is no specified maximum sustained power apart from the connector limits. The connector is defined to supply a maximum sustained current of 6.6 A, which at 12 V nominal limits the form factor to 79.2 W of power. That value is further limited by the operating environment of the host and device. The host manufacturer should provide their requirements and communicate this value as defined by the 12Vpsus definition in SFF-TA-1009. The 79.2 W figure is printed in that sentence and in Table 7-1. It is not an unconditional sustained budget for every thickness. [ta1006]

The revision date and the copyright year are different lines. The title page prints Rev 2.0 December 19, 2025, and the revision history repeats Rev 2.0 December 19, 2025. Page 22, the power page, still carries the footer Copyright © 2026 SNIA. All rights reserved. That footer is not a second revision date. Page 2 is the intellectual-property notice and the permission to copy the document. It is not a power limit. [ta1006]

Table 5-4 is the asymmetric pair, not a second name for the 9.5 mm enclosure. A9a is 25 mm with tolerance +0.35/-0.60, comment Device Thickness including thick enclosure (25 mm). A10a is 19.46 REF, comment PCB to outer thickness with Heatsink (25 mm). A9b is 15 mm with tolerance +0.35/-0.60, and A10b is 9.46 REF for the 15 mm heatsink offset. The symmetric thickness remains Table 5-3 A6, 9.5 mm with tolerance 0.35. [ta1006]

Cooling pressure, flatness, and roughness are three different prints on the symmetric enclosure. Figure 5-3 note 2 says each area shall withstand up to 138 kPa normal to the surface. For the secondary side, this assumes the host supports at a minimum the full contact area of the indicated primary side Cooling Interface Support Areas. For the top or bottom side, the opposite side cooling area is the Cooling Interface Support Area. Table 5-3 prints A11 0.12 MAX for flatness and H1 0.0016 MAX for roughness of the secondary-side cooling interface. Figure 5-3 note 4 says A11 and H1 at minimum apply only to the cooling interface area. Figure 5-4 does not repeat the 138 kPa note. [ta1006]

Direct liquid cooling is a Rev 2.0 change to the 9.5 mm symmetric enclosure, not a new wattage. The revision history says section 5.4 updated drawings, notes, and measurements for that support, and that symmetric enclosures based on Revision 1.6 and older are not compatible, starting with Revision 2.0. Section 5.4 says the device supports either the 1C or 2C card edge as defined in SFF-TA-1002. Section 5.1 says the PCB with a 2C (x8) card edge is not required to meet section 5.2. The same section 5.4 warning says host cold plates should not extend past the cooling interface area. [ta1006]

Datacenter NVMe SSD Specification Version 2.5, cover dated 09282023 and revision-history row 2.5 dated 09/22/2023, adds buyer requirements that SFF-TA-1006 does not print. Section 10.5 FFE1S-10 requires SMBus electrical connections to follow the DC Specification For 3.3V Logic Signaling in SFF-TA-1009 revision 2.0, including Vih1 with a max of 3.465V. FFE1S-12 says a x4 device shall only have a 1C connector. FFE1S-13 says the case (touch) temperature shall not exceed 80°C and that the 100°C TS2 limit does not apply. FFE1S-1 says the device shall adhere to the latest revision of SFF-TA-1006. That 2023 sentence does not name the December 19, 2025 revision, and the Version 2.5 text does not print 12Vpinit or 79.2 W. [ocp25] [ta1006]

Two later tables in the same Version 2.5 document use 12W for something else. Section 20 limits those items to devices delivered to Facebook. FB-CONF-8 is a factory default power state: 6 (12W) is the 2TB row of E1.S 25mm, while the 4TB row is 5 (14W) and the E1.S 9.5mm 1 TB row is 8 (8.25W). META-PERF-8 prints 12W as the max average power for a 4TB E1.S device to achieve all performance targets, with 8.5W, 10W, and 14W on the 1TB, 2TB, and 8TB rows. None of those cells is Table 7-1's 12 W initial slot power limit for a 5.9 mm or 8.01 mm device. [ocp25] [ta1006]

Compared to neighbors

A 12 W cell can be Table 7-1 12Vpinit for the 5.9/8.01 mm column, FB-CONF-8 power state 6 (12W) for a 2TB 25 mm device, or META-PERF-8's 4TB performance-target power. The 79.2 W connector cell is a fourth figure, and it is still limited by the host.

Printed E1.S limits. Each row is the figure in that table, not a substitute for the others.
Record	Printed figure	Not the same as
Table 7-1 12Vpinit, 5.9/8.01 mm	12 W, labeled Initial Slot Power Limit(12Vpinit). [ta1006]	The 25 W column. That cell is only the 9.5/15/25 mm thickness.
Table 7-1 12Vpinit, 9.5/15/25 mm	25 W. Section 7.3 says there is no specified maximum sustained power apart from the connector. [ta1006]	A sustained cap. The connector row is a different cell.
Table 7-1 connector capability	Up to 79.2 W at 12 V, one cell across both thickness columns. Section 7.3 prints 6.6 A at 12 V nominal. [ta1006]	An unconditional budget. The same section says the host and device environment limit it further.
Table 5-4 asymmetric thickness	A9a 25 mm +0.35/-0.60 and A10a 19.46 REF. A9b 15 mm +0.35/-0.60 and A10b 9.46 REF. [ta1006]	The symmetric A6 row, which prints 9.5 mm with tolerance 0.35.
Figure 5-3 note 2	Each area shall withstand up to 138 kPa normal to the surface, with the secondary-side contact assumption. [ta1006]	Figure 5-4. The asymmetric drawing's printed note is the grounding contact only.
Table 5-3 A11 and H1	A11 0.12 MAX flatness and H1 0.0016 MAX roughness, millimeters column. Note 4 limits that minimum scope to the cooling interface area. [ta1006]	The 138 kPa pressure note. Flatness and roughness are separate rows.
OCP FFE1S-13 and FFE1S-10	Case (touch) temperature shall not exceed 80°C, the 100°C TS2 limit does not apply, and Vih1 has a max of 3.465V. [ocp25]	A row in SFF-TA-1006 Table 7-1. Section 7.2 points thermals to SFF-TA-1023 and does not print 80°C.
OCP section 20, Facebook deliveries	FB-CONF-8 prints 6 (12W) for E1.S 25mm at 2TB and 8 (8.25W) for E1.S 9.5mm at 1 TB. META-PERF-8 prints 12W for E1.S at 4TB. [ocp25]	Table 7-1's 12 W 12Vpinit, which is the 5.9/8.01 mm initial slot power limit.

Strengths

Five printed thicknesses — Section 5.1 lists a 5.9 mm form factor, an 8.01 mm form factor with an optional heat spreader, a 9.5 mm form factor with an optional symmetrical enclosure, and 15 mm and 25 mm form factors with an optional asymmetric enclosure. Section 3.3 defines 1U as 1 standard unit or rack unit of 44.45 mm (1.75 inches). [ta1006]
Asymmetric enclosure offsets are not the 9.5 mm row — Table 5-4 prints A9a 25 mm with tolerance +0.35/-0.60 and A10a 19.46 REF, comment PCB to outer thickness with Heatsink (25 mm), and A9b 15 mm with the same +0.35/-0.60 tolerance and A10b 9.46 REF for the 15 mm heatsink offset. Table 5-3 prints the symmetric enclosure thickness as A6 9.5 mm with tolerance 0.35. [ta1006]
The connector ceiling is one merged cell — Table 7-1 prints maximum device power capability as up to 79.2 W at 12 V across both thickness columns, limited by the current capability of SFF-TA-1002. Section 7.3 prints the same 79.2 W from a sustained connector current of 6.6 A at 12 V nominal. [ta1006]

Limits

12 W and 25 W are 12Vpinit, and each belongs to one thickness column — Table 7-1 labels the row Initial Slot Power Limit(12Vpinit), prints 12 W under E1.S (5.9/8.01 mm Thickness), and prints 25 W under E1.S (9.5/15/25 mm Thickness). Informative section 7.3 says there is no specified maximum sustained power for this device apart from the connector limits, and that the connector value is further limited by the operating environment of the host and device. [ta1006]
The © 2026 footer is not the revision date — The title page and the revision history print Rev 2.0 December 19, 2025. Page 22, which holds Table 7-1, prints Copyright © 2026 SNIA in the footer. Page 2 is the intellectual-property and copyright-permission text and does not print these wattages. [ta1006]
138 kPa is Figure 5-3, not Figure 5-4 — In section 5.4, Figure 5-3 note 2 prints that each area shall withstand up to 138 kPa normal to the surface, and that the secondary side assumes the host supports at a minimum the full contact area of the indicated primary side Cooling Interface Support Areas. Figure 5-4, the asymmetric enclosure drawing, prints only the grounding-contact note. [ta1006]
Flatness and roughness are not the pressure note — Table 5-3 prints A11 as 0.12 MAX, flatness for the cooling interface area on the secondary side, and H1 as 0.0016 MAX, roughness for that area, both in the millimeters column. Figure 5-3 note 4 prints that A11 and H1 at minimum apply only to the cooling interface area. [ta1006]
Rev 2.0 changes the 9.5 mm symmetric enclosure — The Rev 2.0 history entry, dated December 19, 2025, says section 5.4 was updated for direct liquid cooling of the optional symmetric enclosure (E1.S 9.5 mm), and that symmetric enclosures based on Revision 1.6 and older are not compatible, starting with Revision 2.0. Section 5.4 warns that secondary-side force in a direct liquid cooling use should not put excessive shear on the card edge and connector, and that this is a host responsibility. [ta1006]
The 80°C case line and the 3.465 V SMBus line are not in SFF-TA-1006 — Datacenter NVMe SSD Specification Version 2.5 (09282023) section 10.5 FFE1S-13 prints that the case (touch) temperature shall not exceed 80°C and that the 100°C TS2 limit does not apply. FFE1S-10 prints that the SMBus electrical connections shall follow the DC Specification For 3.3V Logic Signaling as defined in SFF-TA-1009 revision 2.0, including Vih1 with a max of 3.465V. SFF-TA-1006 section 7.2 points thermal requirements to SFF-TA-1023 and does not print 80°C. [ocp25] [ta1006]
A buyer default power state is not 12Vpinit — Section 20 says its items apply specifically to devices delivered to Facebook. FB-CONF-8 prints E1.S 25mm factory defaults of 7 (10W) at 1 TB, 6 (12W) at 2TB, 5 (14W) at 4TB, and 4 (16W) at 8 TB, and E1.S 9.5mm defaults of 8 (8.25W) at 1 TB and 7 (10W) at 2 TB. META-PERF-8 prints 12W only as the 4TB E1.S max average power to achieve all performance targets, beside 8.5W, 10W, and 14W for 1TB, 2TB, and 8TB. [ocp25]

Typical fits

Checking whether a quoted E1.S wattage is 12Vpinit for one thickness, the 79.2 W connector capability, or a section 20 factory default.
Separating the symmetric-enclosure 138 kPa note from the 15 mm and 25 mm Table 5-4 thickness rows.
Reading the 80°C case limit and the 3.465V Vih1 line as Version 2.5 section 10.5, not as SFF-TA-1006 Rev 2.0.

Uncertainty notes

The 79.2 W figures are printed in Table 7-1 and in section 7.3. They are not a separate arithmetic note.
Figure 5-3 note 2 is the only 138 kPa sentence. Figure 5-4 does not repeat it. Absence of that sentence on the asymmetric drawing is not a finding that those enclosures have no pressure requirement in another document.
Version 2.5 section 10.5 was checked for FFE1S-10 and FFE1S-13. The Version 2.5 text does not print 12Vpinit, 79.2 W, or December 19, 2025. FFE1S-1 says latest revision of SFF-TA-1006 without naming Rev 2.0.
Section 20 wattages apply to devices delivered to Facebook. They are not a second SFF-TA-1006 power table.

Sources

01SFF-TA-1006 Enterprise and Datacenter 1U Short Device Form Factor (E1.S), Rev 2.0, December 19, 2025 · accessed 2026-11-02
02Open Compute Project: Datacenter NVMe SSD Specification, Version 2.5 (09282023) · accessed 2026-11-02