10GbE Network Adapters for Servers

SFP+ or 10GBASE-T

Pick the port type before the chipset, because it decides what plugs in at the other end.

Broadcom documents the 57412 as two 10Gb SFP+ ports and the 57416 as two 10GBASE-T ports, each built as a PCIe Gen3 x8 card or an OCP 3.0 card.

SFP+ and 10GBASE-T cards side by side

The two port types differ in power, slot width and what they can fall back to, not just in cabling. Intel's product briefs for its X710 (SFP+) and X550 (10GBASE-T) adapters give a like-for-like comparison:

Using a 10Gb card on a 1Gb network

A 10GBASE-T card drops to gigabit by itself: Intel's X550 auto-negotiates 1, 2.5, 5 and 10GbE and is backward compatible with 1000BASE-T networks, so it links to a gigabit switch over the same RJ45 cable. An SFP+ card needs a 1G optic in the cage and an adapter that supports 1GbE; Intel lists 1GbE for optical modules on its X710 but 10GbE only for direct-attach cables. For links that stay at gigabit, see gigabit network adapters.

Slots and other form factors

This category holds slot cards: PCIe adapters and OCP NICs. Dell's R750 guide shows the 15th-generation PowerEdge trading the rNDC slot for OCP 3.0, so OCP cards suit those servers while PCIe cards fit any free slot of the right height. Dell rNDCs and blade cards have their own pages, network daughter cards and mezzanine adapters, and cards bought for FCoE or iSCSI storage offload are under converged network adapters.

Pair SFP+ cards with 10GBASE-SR SFP+ transceivers or direct-attach cables. Other speeds and port counts: dual-port, quad-port, gigabit and 25GbE adapters, all in cards and controllers. Every card is sold with an Enterasource warranty, and the listing says for how long.

The switch side of these links is covered on 10GbE switches.

10Gb network card questions

What cable does a 10Gb network card need?

It depends on the port. An SFP+ card takes an SFP+ direct-attach cable, which Cisco builds as passive cables of 1 to 5 m and active ones of 7 or 10 m, or an optic: 10GBASE-SR over OM3 or OM4 multimode to 300 or 400 m, or 10GBASE-LR over single-mode to 10 km. A 10GBASE-T card takes Cat 6A twisted pair to 100 m or Cat 6 to 55 m, per Intel.

Will a 10Gb card work with my 1Gb switch?

A 10GBASE-T card will: it auto-negotiates down to 1GbE over an RJ45 cable, as Intel's X550 brief describes. An SFP+ card works only with a 1G SFP optic in the cage and an adapter that supports 1GbE, which Intel's X710 does on optical modules but not on direct-attach cables. A 10G direct-attach cable will not link to a 1G SFP port.

SFP+ or 10GBASE-T?

Choose by the far end and the cabling already installed. SFP+ suits racks whose switch has SFP+ ports, short direct-attach runs and lower power, about 3.3 to 4.3 W per dual-port Intel card. 10GBASE-T suits buildings wired with Cat 6A and switches with RJ45 ports, and it falls back to 1GbE, at about 11.2 W per dual-port card.