And I say don't give him yellow card.
First, because either you or me misinterpretted the other one. If your posting style is to repeat "asshole" towards me, feel free to do it, I've explained already why that particular word doesn't bother me. As long as I don't see "cretin" or something like that, we're fine.
I never ment desktop PCs, of course you'll disable integrated GPU in them and it's probably disabled by default. At least for a while… I'll come to that later.
In laptops is as I said another story. Didn't suck it out of my pinkie, there is a good reason why laptops by default come with both GPU enabled (if they have a separate card, ofc) and also why nVidia Control Panel and Ati Catalyst have an option to force software exe to use a specific GPU, but well, I suppose you don't have to trust me:
http://computers.toptenreviews.com/gaming-laptops/graphics-cards-integrated-vs.-dedicated.html
One more thing. You're also assuming I didn't build any PC in my life and dunno what am I talking about. Just don't, please, because I did. Please, always assume I just don't want to harm or scam people. Even when my post sounds rude. I just make a message, it's people's choice what they'll do next. Thankyou.
To return back why in a while disabling GPU will become counterproductive in desktops - it's win10.
Not everyone will switch on it instantly, but many will, at least to test it.
DX12 brings something IMO spectacular, and it's using both GPUs at the same time for calculations (currently, using both is available only as multimonitor output support). In normal words - DX12 should improve your machine performance if you don't disable integrated GPU.
I'm not saying we'll all be enabling integrated GPU on desktops, especially people who are with SLI or Crossfire duos, some even with quads. But the majority who use singleGPU machine will love the feature (assuming it will work without problems and assuming the performance won't be boosted by just 1-3%).
More on it:
http://www.pcgamer.com/directx-12-will-be-able-to-use-your-integrated-gpu-to-improve-performance/#!
That'd be it. If there is a need for step by step how to set an app to use a specific GPU in it's tools options, I'll post it.