Odd Package C-State behavior depending on Array Device status

Hi all,

I've observed an odd behaviour in the package C-States of my Unraid machine that's configured as follows:

Unraid Version: 6.12.13

Mainboard: Fujitsu D3417-B2 (Bios Version V5.0.0.12 R1.26.0)

CPU: Intel I5-7500

Memory: 32GiB DDR4

Array HDD: 6x 4 TB WD Red (WD40EFRX)

Cache SSD: Samsung 970 Evo Plus 1 TB

PSU: Corsair RM650x

I extended my array of previously 4 Devices (4x WD40EFRX-68WTONO) with two more hard drives (2x WD40EFRX-68N32N0).

As long as the new never devices are spinning, the system is able to enter Package state C8. As soon as one of the two newer drives is spinning down, the system is only able to reach Package state C7.

Has anyone else ever experienced a similar behavior or does anyone know where it comes from and how to solve it?

I attached two images, one where powertop is clearly indicating C7 as the highest C-State while the drives are down and one where powertop is indicating C8 while disk 4 and disk 5 are up and I attached some hard drive data obtained through hdparm (sde for comparison as well as sdf and sdg).

Thanks for you help.

Best,

Max

hdparm_dev_info.txt