r730xd Server Part 2: Lowering Idle Power

 As the plan is to have the server on 24/7, I wanted to lower the idle power usage. All power numbers were manually captured from a smart outlet.

Baseline

1 x e3-1225v3, 4 x 8GB, 1 SSD, 2 x WD Red Plus 6TB, 1 x JMB585

• in Ubuntu no load
• ~35W

2 x e5-2670v3, 8 x 16GB, 1 x 10K 2.5" SAS

• in Proxmox no load
• ~95W (93.6 to 100)
• 4% fans
• stress -c 48
• 290W
• 8% fans
• 70C + 77C (inlet 16C, exhaust 39C)

Removing a processor

This will lower the PCIe connectivity, but should save power. To be able to remove a processor, I needed to buy a CPU socket cover and an airflow guide

• Socket 2011-3 cover: $6.99 + tax
• Dell CPU Blank airflow guide 21PJD: $11.02 + tax
• Note: this will not allow you to install blanks into the memory slots so dust could be an issue
• Updated total: $452 + tax

1 x e5-2670v3, 4 x 16GB, 1 x 10K 2.5" SAS

• in Proxmox no load
• ~81W (80.5 to 85.4)
• 4% fans
• stress -c 24
• 166W
• 8% fans
• 67C (inlet 15C, exhaust 27C)

1 x e5-2670v3, 8 x 16GB, 1 x 10K 2.5" SAS

• in Proxmox no load
• ~82W (81.4 to 85.2)
• 4% fans
• stress -c 24
• 174W
• 8% fans
• 68C (inlet 15C, exhaust 27C)

This means that the memory used only about ~1W at idle for all 4 sticks and ~8W at full load. This means that running a single processor will save me about 13W.

Adding a second drive

Adding the second 1.2TB SAS drive increased my idle power usage by ~4.5W

• in Proxmox no load
• ~86.5W
• 4% fans

Making the jump from a Xeon v3 (22nm) to v4 (14nm)

For this upgrade I bought used processors

• 2 x 2680 v4: $21.58 + tax
• Updated total: $474 + tax

I moved from a 2670 v3 to a 2680 v4 in hopes that it would shave off a couple of watts at idle, unfortunately it uses ~1.5W more. So it seems that each core uses about 1W at idle.

• in Proxmox no load
• ~88W (87.4 to 89.1)
• 4% fans
• stress -c 28
• 205-206W
• 80C (inlet 17C, exhaust 30C)

While not improving the idle power usage, it will be a large boost in both single-core (13%) and multi-core performance (23%) https://www.cpubenchmark.net/compare/2779vs2337/Intel-Xeon-E5-2680-v4-vs-Intel-Xeon-E5-2670-v3

Setting governor to powersave

Tried changing the governor to save idle power, but did not notice any change.

• apt-get install linux-cpupower
• cpupower frequency-set -g powersave

Appendix

Sources

• https://wiki.archlinux.org/title/CPU_frequency_scaling#Scaling_governors