I bought "Die-Wu ASM1166 6 port SATA PCIEx2 adapter from aliexpress" it has red heatsink and red SATA ports on back of card.
In mean time ordered ECS06 just in case and to be honest it's not always an easy task to upgrade this ASM1166.
Even with SilverStone I had couple failes when software didn't recognize my card properly, found out that I already had latest firmware on ECS06 but flashed in anyway - if there are any problems just start flashing software once again until it'll say "It can take some time to detect devices - please be patient".
So let's dive into Die-Wu -> it was not recognized (used same software that came with ECS06) - and firmware was outdated from 2019, but I managed to flash it without any major issues - now it has same firmware (you can check this on POST screen).
Currently I need to figure out idle power consumption with NVME disk installed - once I have that data I'll check both cards power consumption and C8 power states.
EDIT#1
With Die-Wu power consumption goes up from ~ 8 W to ~ 13 W on average measured on wall plug. Way more than mentioned 2 W. I used powertop tunning at beggining then run powertop --auto-tune just to make sure - we're loosing C8.
EDIT#2
With SilverStone ECS06 installed I'm reading same consumption as on Die-Wu - ~ 13 W maybe a 0.1-0.2 W less - but this proves that actual power consumption is around 4 W not 2 W.
EDIT#3
So I've got 9211-8i flashed in IT mode and well this thing itself without HDD connected draws 8.5 W !! So power consumption goes up from 8 W without any card to 16.5 W in idle - same Unraid, same plugins, same setup. This is insane to be honest. I've got same measuring device - exactly same setup. And system takes 8 W and HBA card more than that...