I use some modded drivers on my laptop to get the hybrid (or switchable) graphics working. HP has yet to release proper windows 8 drivers for my computer. Which is odd because they have already released some windows 8 drivers for my computer along with a bios update. Trying to install switchable graphics in compatibility mode for windows 7 fails. Windows update will install the latest drivers, but that won't install the components necessary to make them switch back and forth.
I look at leshcat and after trying X, Y, Z solution I found at least an half solution to my problem with your suggestion.
The solution I found the most usefull to me now is that:
After installing Windows 8, erase atiilhag.inf and atiilhag.pnf file in C:\Windows\Inf folder.
Uninstall both device in Device Manager, with the first that is not used and the used one after so windows will replace it with his one default.
Install the leshcat driver, a version which is compatible with Windows 8 and the only ones is with a stupid Intel Graphics Unit which it's not my case.
I guess we must stay plugged in or it will select the poor GPU by default which it's not a good idea.
After it's installed and it using the High Performance GPU, don't switch your GPU or we are gonna to get back to the same problem.
You can update your driver with Windows Update so you can have more feature than the driver provided with leshcat.
After all of this, I just have to make sure to not switch my GPU with the Switchable Graphic Application and make sure that the automatic Switch is not checked.
The good point is I can have my High Performance Graphics working correctly.
The bad point, I still have a power consumption problem.
My Low Power GPU unit is under control of the Basic Graphic Driver from Windows, and I think, it is still running even if I don't use it.
Thank anyway Mr. Android.
It's a good start.