10Gbe and lower c states

[Napoleon]

Trying to setup 10Gbe, but considering power consumption.

 

I have 3 devices that need connecting to each other and a switch with only 2 10 Gbe ports and to hand an X520, X540, X550, all RJ45 2 port, but also an SFP Broadcom 57810/Dell 0N20KJ which are cheap on ebay. Do all of these reach lower power states?

Many state idle power consumption for the cards, but I've also read someone tried an X520 and it didn't increase idle power consumption as it wasn't being used. Is that the case with all the Intel cards? It'll only consume power when being used? The main question is whether it'd be worth shelling out for 2 other SFP cards and cables.

Considering ditching the 10gbe switch, connecting the 3 devices directly to each other with the intel card and using the 1gbe to connect to the network which hopefully mean they only use power when they get used.


 

 

[_cjd_]

SFP+ DAC is lower power consumption at the switch... 0.1w fiber DAC, best rj45 I see is 1.8w when it's up (x540 on the other end) and 2+ (x550 on the other end) - note different transceivers so that's likely the difference, not the nic. I haven't tried pulling a copper DAC but it's going to be better than fiber. All 8 ports up on my Ubiquity Aggregation switch is still under 13w measured by a Shelly plug, just the two rj45 transceivers.

X710 with the right firmware I recall can do higher c-states, forget which else. I haven't tried pushing hard on the system with the x540, it's my backup unraid and is rarely powered on. Older i3, idles around 28w. Check the powertop thread, this has come up multiple times.

[Napoleon]

Thanks. So if a switch isn't in the equation and they aren't being used, what do they add to the idle power consumption? Is there any difference between C state achieved on the x520, 540 and 550?

The X550 is PCIE 3 x8. If I put this in a x1, will it still achieve 1GB is one port is used at a time? PCIE3 x1 limit is 10GB/s.