Well, most of the time everything is just idling in my home server. The power consumption of my TX1320-M3 with 64 GB RAM, 2 NVMe operating system disks and 6 SATA SSDs currently is about 20 W. The 6 SATA SSDs may have increased power usage by 6 W, sadly I don't have exact numbers by hand.
I know these problems.ASPM is activated in BIOS but there is already a device, that does not support it: the Matrox graphics card. As I'm running FreeBSD I don't have exact numbers because the lack of the nice powertop, but at least C3 states are reached by the CPU
20W at "only" PC3 and with 6 SSDs + 2xNVME and only 1W/SSD at Idle

? That's VERY good actually. Do you trust your "Kill-A-Watt" Measurement Device though ? Or is it oscillating a lot / "unstable" ?
Are you sure that is the "Package" C-State though ?
I don't have much experience with FreeBSD, just a bit a long Time ago and some headaches trying to build some Ports/Packages on OPNSense

.
Lucky you that it works though. It MIGHT also work on Linux but it was disabled for a Reason, not sure it's worth the Risk of compiling a Kernel from Source with that Patch/Quirk removed.
Still my initial question was more about cooling of these cards. I doubt that a 13 W device with small heat sink is cooled down enough.
Well given that there is almost no Airflow in the Chassis with significant Static Pressure I'd tend to agree. My Issue was on the Silverstone ML03 with 4 Fans blowing Air into the Chassis. With 2 Fans failed, the HBA/NIC were cooking essentially.
Put some 40mm or possibly 60mm Noctua on it or something

.
On the cheap there are
plenty of 40mm Fans also on
Digikey that you can buy also from relatively Reputable Brands (let alone Aliexpress, Amazon, ... although I'd say they can be more Expensive). I'll have to investigate whether it's possible to replace those proprietary 70mm Fans with some standard 80mm ones. I was thinking of using some 3D Printed Adapter for 70mm -> 80mm Fans that can be found on Thingiverse (e.g.
this) or similar Sites. Since I don't have a 3D Printer, I'll have to order online I guess. Not sure if there are other Locations where it's possible to add a Chassis Fan though.
Not sure why Sunon requires some additional Protection though (fuse), that seems stupid. Unless this is because it's meant for System Integrators and NOT targeted to Motherboards as an End-Product. Indeed you'll need to crimp these and make a Connector (not a huge deal given it's 2x Cheaper than the others).