OK...now that I understand what you are attempting...I will tell you not to!
You may ask why at this point, and that would be a good question!
The answer is fairly simple, but has more complicated explanations behind it which I will not go into!: ) (many
in this post already!)
OK:
Don;t mess with your priorty allocation.
Windows (XP and up) is clever enough to assign it's priorty based on user input.
In your example of browser, game and notepad you can only input commands to one of them at a time (possibly two if you have multiple input devices, multiple screens and an extra pair of hands) (you don't have extra hands do you? If you do...can you give me a pic...that would be a first for me!)
When you have a game full screen (heck, even if it's not full screen with modern games) it will actively set it's processor affinity to the maximum the game's programmers have given it.
If you are a WoW player, you might remember back a few years when Blizzard upped the support of WoW to include a full i7's 8 cores and gave us the ability to manually change the number of cores, and indeed which cores we wanted to use (I always chose physical core 1,2 and 3) (note: not core 0 - I wanted that core free for windows to 'own)
I also didn't use the hyperthreaded cores as they were not needed.
When I loaded my WoW setup for multiboxing on a single machine I simply chose a core for each install of WoW.
This is a good example of what you are trying to achieve I believe.
It should also show that you are barking up the wrong tree for what you are trying to achieve.
If you want to have better priorty you change the affintiy of the CPU cores for the application (if the application has the ability to have this done) (and yes, windows can do this to some extent, though I've not played with it in Windows 8!)
Now for why you don't change the priorty:
An example:
Game A is loaded and running in 'real-time' (which it is basiclly trying to ignore anyway) and your browser is loaded in the background.
You have a download going on when suddenly the PC is attacked by a virus.
At this point your AV tries to kick in and can't because you have assigned 'real-time' to another application and the AV can't break that process....hello little virus...welcome to my game, now if the virus is a good one, and by good I mean pure evil!, it will hijack the active process, infect it and then propogate using the active process' priorty....
That is an EXTREME case and not entirely accurate, but highlights the possibility that could befall you.
Let me know if any of that made any form of sense at all.