And by "this phenomenon", you refer to the main question, the lag when encountering a Pokemon?
I'm not too good with computers, but if 'task manager > set priority > high' should do the trick regarding the power settings, then unfortunately it doesn't change anything performance-wise. Encountering a wild Pokemon still takes ~7 seconds.
I'd also like to add, it doesn't really matter how much I have going on the background. The issue really is just the encounter-lag, its time doesn't increase or decrease whether I have more running in the background. Nor does it create other issues, such as lag during screen transactions or any form of stuttering.
I suppose it could be my computer, yes, but shouldn't I have other difficulties too then? Or at least, that other games, like Reborn, show any issues? Because they have no problems whatsoever, they play perfectly.