MacBook Pro Radeon 460 takes battery even if not used

I use the new MacBook Pro Late 2016 15" with the new AMD Radeon 460 and got a little bit stuck with the battery usage. As I can see in iStat Menus even if the internal GPU is used (which I check with gfxCardStatus) the discrete GPU uses up to 10W of power.

Only sometimes, e. g. on starting the system without using an external monitor or any other app, which uses the discrete GPU, it is at nearly 0W.

Is this a general problem with the MacBook Pro, a software problem or something different?

I already reinstalled the system but it didn’t help.

Just to be precise: If the Radeon 460 is active on battery consumption even if it isn’t used the system goes to sleep after ~3 hours. If it is not, the system goes to sleep after 7–10 hours. So it is a huge difference.

So any help is appreciated. 🙂