In short: a 10G copper SFP+ (10GBASE-T) module is a good option when you need to connect a device with a 10G RJ45 port to an SFP+ port over a short network cable – up to about 30 m. For links inside a rack a direct attach cable is cheaper and cooler, and for anything longer, fiber is the better choice.
Here is how 10G over copper compares with fiber and DAC, and when each one makes sense.
What a 10G copper SFP+ module does
The SFP-10G-T module turns an SFP+ port into a normal RJ45 network port that runs at 10 Gbit/s. You plug a standard network cable into it, exactly as you would into a copper switch port. Many modules can also run at lower speeds when the device on the other end does – check the product details if you need that.
10G copper vs fiber vs DAC
| 10GBASE-T copper | DAC | Fiber (SR / LR) | |
|---|---|---|---|
| Cable | standard network cable (Cat6a or better) | fixed twinax cable | fiber patch cable |
| Typical reach | up to 30 m | 0.5–10 m | 300 m (SR) to 80 km (ZR) |
| Power and heat | highest | lowest | low |
| Best for | devices that only have RJ45 ports | inside a rack | everything longer |
When 10G copper is the right choice
- The other device only has RJ45: servers, NAS systems or workstations with 10G copper network cards.
- Existing copper cabling: when good network cabling is already in place and the distance is short.
- A few ports, not a whole switch: when you need a couple of copper connections on an otherwise fiber-based switch.
What to keep in mind
- Heat: 10G over copper needs more power than an optical module, so the module runs warm. Some switches limit how many copper modules can sit next to each other – check your device's documentation if you plan to use many.
- Cable quality: use Cat6a or better for the full 10G distance.
- Distance: about 30 m is the practical limit for 10G copper modules. For longer runs, use fiber.
Inside the rack? Use a direct attach cableCheaper and cooler than copper modules – 0.5 to 10 m.
The alternatives
If both devices have SFP+ ports and sit in the same rack, a direct attach cable is the simplest and most energy-efficient choice. For anything beyond the rack, optical modules over fiber are cooler, reach much further and are not affected by electrical interference – see 10G SFP+ types.
Frequently asked questions
Is 10G copper as fast as 10G fiber?
Both carry 10 Gbit/s. The differences are in distance, power use and the type of cable.
Which network cable do I need for 10GBASE-T?
Cat6a or better for the full distance. Older cable may work over shorter runs, but it is not guaranteed.
Do 10G copper modules work in every SFP+ port?
Most SFP+ ports accept them, but some devices limit their number because of power and heat. As with any module, it also has to be coded for your equipment – see our SFP compatibility guide.
