It was this board: https://www.supermicro.com/en/products/motherboard/a2sdi-2c-hln4f https://www.supermicro.com/en/products/motherboard/a2sdi-2c-... I think it

It was this board: https://www.supermicro.com/en/products/motherboard/a2sdi-2c-hln4f https://www.supermicro.com/en/products/motherboard/a2sdi-2c-... I think it was idling at something like 30-40W with four HDDs and a UPS. I didn't have an especially efficient PSU and the UPS must have taken some power too. The motherboard alone would draw as little as 15W, I suppose.