How can enable switchable graphics in Windows 8.1 (Bootcamp)

Question

So I just dropped $3,000 on a high end (late 2013) 15" rMBP and immediately installed Windows 8, and then 8.1, through Bootcamp. I need Windows for a lot of engineering programs, as well as occasional gaming. I bought a MacBook because I prefer OSX for programming - I love Ubuntu, but my previous laptop had driver issues (ironically enough, also due to the graphics card) that would cause it to overheat and only give me about 45 minutes of battery life.
After using it for a little, I realized that the MacBook was VERY hot. I closed all of the power intensive applications and proceeded to browse reddit on low brightness and power saving settings to let it cool down, but it did not cool down much. I shut it down, and turned it on about 15 minutes later, when it had successfully cooled down. I realized that just being booted into Windows caused the laptop to get unreasonably warm - I'm assuming that it's because I have the Nvidia GeForce GT 750M graphics card in it. I can not seem to find an option to enable power saving graphics.
Is there any way to use the integrated Intel graphics rather than the discrete card? Not being able to run Windows reasonably well would really make me regret this purchase, especially when I could have bought a different laptop for much less and installed a Linux distro on it.
Any help is appreciated.

Answer 1

Sorry, but I think the above post is bad advice.  It's unlikely to be a fan issue as these are generally controlled by firmware.  If your laptop is getting very hot in Windows with only minimal and light use then that suggests a power management issue.
The first thing you'll want to do is check that your Power Management settings are not set to "High Performance".  A lot of people select this option thinking it gives them the most out of their computer and hardware purchase without realising what it does and that it comes with significant issues and tradeoffs.
What the High Performance setting does is disable CPU throttling, forcing the CPU to run at its maximum speed constantly (on all cores) and draw its maximum power load, even when not required.  This causes the laptop to heat up very hot very quickly even if you aren't doing much, while simultaneously killing battery life.  If you found a way to replicate this behaviour in OS X (and turn graphics switching off) you'd find the laptop would get equally hot and fans would ramp up to maximum speed just to try to keep things cool.  If you hear your fans spinning at maximum then that is evidence that fan control is working.
It's a very unnatural behaviour and there are almost no situations where you ever need to use it.  Microsoft should really make an effort to hide it and make it harder to access.  High performance sounds nice and "Why wouldn't I want my laptop to run with high performance" is what most people think.  Of course, Microsoft isn't very good at understanding what people think.
For most purposes "Balanced" is the Power management setting you'll want to use and this more closely reflects what Apple uses in OS X.  Failing this, it could be that whatever software you're using is very badly coded for power management, but this is less likely and unlikely to cause the severe heating issue you described.
Finally, there's no need to regret your purchase.  It's an amazing laptop and the best way to run Windows in my opinion.  The only thing missing I can think of is switchable graphics driver support but this isn't anywhere near as severe a problem as what you've described.