Since I can't see your code, I can't exactly help with the 32bit vs 64bit build, and you seem to be saying that the two builds you are using are different, and both seem to be different to what is on screen.
But, the variability on the laptop I should be able to manage.
First, are you running the laptop on battery power? If you are, then the laptop has to lower the amount of energy it uses no matter what, since the battery can only put out so much power. This is a much bigger issue if you have a dedicated GPU, but is still applicable to your APU, since the GPU still has to operate within that power budget.
You can always plug it in if it isn't. Most gamers play with their laptops plugged in, though not all.
Second, Windows has power plans that dictate how the processor scales. You can either change your current plans settings to force the CPU to run at 100% at all times, or you can just change the plan to High Performance preset, and change it back during normal operation.
You can do this on Windows 8/8.1 by right clicking the lower left hand corner/ Start Button and selecting "power options" menu item. Then show other power plans on the window that shows up, and choose High Performance.
You could also open the Mobility Center in that same menu, which has power plans as a drop down menu, along with some other useful tools.
Keep in mind this fixes the variability by setting the CPU to operate at 100% at all times, so will use up your battery much faster, so you should only change this when plugged in. Also, this only solves the problem on your machine, you still have to worry about it on other machines.
Also, why do you have 2 different code bases? You should be able to compile the build Casey has on both 32bit and 64bit, since he has kept that in mind and mentioned areas that might need to be changed for the different CPU types.