qBittorrent official forums

I can't post this as a bugreport, because it's hard to pinpoint the actual bug. Let me explain.
Okay where should I start. Please bear with me: I'm on the latest 4.5.0 (I always use x64) release and I got a new video card and because of that I upgraded my chipset driver and BIOS firmware.
I have a Ryzen 5 3600 CPU (6 core - 12 threads) and after the updates I noticed that my idle CPU power consumption went up from 12-15w to CONSTANT MINIMUM 25 watts but I didn't checked it like 1-2 years. Okay, maybe because of the updates what I mentioned. It never occurred in me to close qBittorrent, because it was never a performance hog. Of course I closed every app and checked qBittorrent: no transfer...0,2-0,7% CPU usage...25w power consumption. Okay, I'll close it too and BAM, Power consumption dropped to 12w. As if it prevented all my cores entering C6 state because of aggressive core management or something.

Okay, this was clearly not an issue 1-2 years before. I digged out an old version of qBittorrent: 4.1.2. And...CPU is back to 12-18w. WIN. But from which version it went from good to bad?
I tested a bunch of it and found it!

In 4.2.5 the CPU handling was still good but in the 4.3.0 it went up to 25w idle just like in the latest (4.5.0) version.
So something happened in the 4.3.0 which is still present in the latest release. It's a wild guess but maybe it got some extra - pointless - multithreading in it which dramatically increases core jumping.

I know this is a very hard bug to debug but a lot of people are using qBittorrent and this extra power consumption multiplied by all the users...it's huge.

I mean, I can't speak for the team, but this would be nearly impossible to debug.
qBittorrent is "just" a portion of what you use as qBittorrent. It relies on Qt, it relies on libtorrent, and many other libraries. Each release is built with a set of these - sometimes, you have multiple builds for a release. 4.5.0 has qt6 variant, lt20 variant. I mean, you could certainly check on the News portion of the main website, see what 4.1.2 used, and you could try messing around, producing new builds.

https://github.com/qbittorrent/qBittorrent/wiki

Just go down to Compilation.
If you don't want to end up with a ton of junk on your main system, you can always use Virtualbox for example to create a build environment, and you'd just copy out the executables I suppose.

CPU is back to 12-18w.

How do you measure consumption? Ryzen Master?

this extra power consumption

I would not really worry about it. For now, it's just one processor, from one generation. Thing is, older CPUs were worse at power saving (like 1000 series Ryzen and before). And new ones... are too. And we are in the "power wars" once again, where manufacturers are trying to pump as much juice as possible into the chips. AMD, Intel, Nvidia are all guilty of this at the moment. AMD, who was an efficiency king until the 7000 series, is doing it now. So not much hope left.

So yeah, instead of using 7W more in idle, they are now pushing +100-300W more during use easy.

Ps.: Oh and I forgot... most motherboards don't even enable further power savings by default.