thanks for the pointer. I will experiment with downvolting the CPU.
Right now I am trying to be consistent in my testing methodology, which is to only enable BIOS features that define ‘power savings’ - because I think the BIOS and motherboard is what drives most of the idle power draw and common motherboards on sale today are not focused on power savings like server boards like AsRockRack - but I am hoping thru my testing some of them come to light.
Here’s some results for the B660M AORUS PRO AX DDR4 - lowest 24.5 watts idle (2 nvme, proxmox, ‘powersave’ cpu scaling governor, ‘powertop --auto-tune’ plus all BIOS settings except downvolting).
This board is in the same league as the ASUS from the start, two things I noticed in the AORUS BIOS were:
- you can’t disable WIFI/Bluetooth (likely costing some 1-2watt idle efficiency)
- can’t disable USB 3.2 controller
- disabling built-in soundcard does not seem to do anything, linux still sees the device when it should be off.
- IOMMU groups are not an issue and well separated m.2 slots.
IOMMU Group 0:
00:00.0 Host bridge [0600]: Intel Corporation Device [8086:4630] (rev 05)
IOMMU Group 1:
00:02.0 VGA compatible controller [0300]: Intel Corporation Alder Lake-S GT1 [UHD Graphics 730] [8086:4692] (rev 0c)
IOMMU Group 2:
00:06.0 PCI bridge [0604]: Intel Corporation 12th Gen Core Processor PCI Express x4 Controller #0 [8086:464d] (rev 05)
IOMMU Group 3:
00:0a.0 Signal processing controller [1180]: Intel Corporation Platform Monitoring Technology [8086:467d] (rev 01)
IOMMU Group 4:
00:14.0 USB controller [0c03]: Intel Corporation Alder Lake-S PCH USB 3.2 Gen 2x2 XHCI Controller [8086:7ae0] (rev 11)
00:14.2 RAM memory [0500]: Intel Corporation Alder Lake-S PCH Shared SRAM [8086:7aa7] (rev 11)
IOMMU Group 5:
00:14.3 Network controller [0280]: Intel Corporation Alder Lake-S PCH CNVi WiFi [8086:7af0] (rev 11)
IOMMU Group 6:
00:15.0 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH Serial IO I2C Controller #0 [8086:7acc] (rev 11)
00:15.1 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH Serial IO I2C Controller #1 [8086:7acd] (rev 11)
00:15.2 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH Serial IO I2C Controller #2 [8086:7ace] (rev 11)
00:15.3 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH Serial IO I2C Controller #3 [8086:7acf] (rev 11)
IOMMU Group 7:
00:16.0 Communication controller [0780]: Intel Corporation Alder Lake-S PCH HECI Controller #1 [8086:7ae8] (rev 11)
IOMMU Group 8:
00:19.0 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH Serial IO I2C Controller #4 [8086:7afc] (rev 11)
00:19.1 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH Serial IO I2C Controller #5 [8086:7afd] (rev 11)
IOMMU Group 9:
00:1a.0 PCI bridge [0604]: Intel Corporation Device [8086:7ac8] (rev 11)
IOMMU Group 10:
00:1c.0 PCI bridge [0604]: Intel Corporation Alder Lake-S PCH PCI Express Root Port #1 [8086:7ab8] (rev 11)
IOMMU Group 11:
00:1f.0 ISA bridge [0601]: Intel Corporation Device [8086:7a86] (rev 11)
00:1f.3 Audio device [0403]: Intel Corporation Alder Lake-S HD Audio Controller [8086:7ad0] (rev 11)
00:1f.4 SMBus [0c05]: Intel Corporation Alder Lake-S PCH SMBus Controller [8086:7aa3] (rev 11)
00:1f.5 Serial bus controller [0c80]: Intel Corporation Alder Lake-S PCH SPI Controller [8086:7aa4] (rev 11)
IOMMU Group 12:
01:00.0 Non-Volatile memory controller [0108]: Phison Electronics Corporation E16 PCIe4 NVMe Controller [1987:5016] (rev 01)
IOMMU Group 13:
02:00.0 Non-Volatile memory controller [0108]: Samsung Electronics Co Ltd NVMe SSD Controller SM951/PM951 [144d:a802] (rev 01)
IOMMU Group 14:
03:00.0 Ethernet controller [0200]: Intel Corporation Ethernet Controller I225-V [8086:15f3] (rev 03)