How can enable switchable graphics in Windows 8.1 (Bootcamp)

Install Speedfan. The bootcamp drivers do a terrible job at controlling temperatures and fan speeds.

You might have trouble with it misreading the CPU temperature saying that its 90c when it really isn't. If you have this problem, look at this thread: http://sourceforge.net/p/lubbofancontrol/discussion/970570/thread/8b89d2ad

Also, bootcamp drivers do not support switchable graphics. Either because apple doesn't want windows users to have better battery life or because writing the driver is tedious.

Also, i currently have a problem with searchindexer.exe periodically running and taking up about 10% of the CPU, causing temperatures to rise. Check the resource monitor and see if its running. If so, kill it. Your computer will cool down right away.

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.

MacBook Pros run hotter with discrete graphics on and cooler with intel integrated graphics. On the Mac OSX side, auto graphics switching is on in Mac OSX 10.9.4 Mavericks and runs cooler but for Bootcamp in Windows 8 there is no graphic switching because bootcamp only sees the discrete graphics. I read that it is due to Apple's implementation of EFI and lack of drivers from Microsoft to address the issue.

On both Mac OSX and Windows 8 via Bootcamp, I recommend Macsfancontrol-- it has a MacOSX version and a Bootcamp version to keep your Mac cooler whether you are on Mac OSX or in Windows.