I have tried Dual Graphics on my A10-7850K with an XFX R7 250- 1GB DDR5 (there is no passive cooled R7 250 with DDR3 available on the market). It works well in the games, which I tried.
But why is the dedicated card used when I use Firefox or watch videos? The APU is much more (power-) efficient, while doing things like that.
Is there a way to configure, in which scenario the APU should be preferred and when the discrete card should help?
In my opinion, the discrete graphics card is only an addition in a Dual Graphics configuration. So the main work should ONLY be done by the APU. The discrete card should only work, when more power is needed, than the APU can deliver (e.g. in some gaming situations).