Author Topic: power consumption observations  (Read 348 times)

pocock

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power consumption observations
« on: September 12, 2020, 01:48:31 pm »

I made the following observations using the meter in my UPS, it measures units of approximately 0.1A

Measurements were made with Debian buster in the idle state, at the GNOME login screen.  It actually uses less power there than at the petitboot menu.

Voltage = 240V



Unplugged: 0

BMC powered: ~ 0.1A

Single 8 core CPU installed with 4 memory chips: add 0.3A - 0.4A above the BMC power draw (total, 0.4A = 96W)

Second 8 core CPU installed with 4 more memory chips: add 0.2A - 0.3A above the single 8 core (total, 0.6A = 144W)

These are bare minimum figures in an idle system with RX 580, LSI 9207-4i4e and one SATA SSD

The system doesn't have the SAS option on the board, that would use more watts if present.

HP suggests a comparable single CPU Z8 G4 workstations can use 74W at idle:
https://www8.hp.com/h20195/v2/GetPDF.aspx/c05527763.pdf (page 31)

Their Z4 workstations can go down to about 40W at idle although the spec is more like a Blackbird with 4 core:
https://www8.hp.com/h20195/v2/getpdf.aspx/c05527757.pdf

I feel that for people who are mostly idle and just need an occasional boost of power to compile something from time to time, it may be better to stay on a single CPU and Talos II Lite but for people who need the power regularly for different types of work, the HP and Talos II would end up using similar amounts of power.

For people who leave their workstation on all the time or use it as a file server, the second CPU is wasting a lot of power when idle.  As discussed in another thread, it would be useful to have options to power down some cores
Debian Developer
https://danielpocock.com