Hi there welcome, I can tell you that the rain drops on the visor is a known issue that causes slowdown, it has happened to me. However, upon testing this game on the stable build 4.0.2, I did notice that the slowdown went away and maintained constant speed. Also I do get a few frame drops when alot is happening on screen, but not much so I am suspecting it is a hardware limit.As for the other game I couldn't tell you as I do not have this game. You may want to post your settings for Metroid Prime to see what you have.
[color=#666666]MSI [/color][color=#ff9933]CX[/color][color=#666666]60[/color]
[color=#999999]i5-4200M @ 3.5Ghz [/color][color=#ff9933]turboboost[/color]
[color=#666666]N[/color][color=#999999]vidia GT720[/color][color=#ff9933]M[/color]
[color=#999999][color=#666666]1[/color] [/color][color=#ff9966]TB[/color] [color=#999999]HDD[/color]
[color=#666666]Windows[/color] [color=#ff9933]8.1[/color]
[color=#999999][color=#666666]Wii [/color]Pro Controller [/color][color=#ff9933]+[/color] [color=#999999]Mayflash adapter, Wii Mote [/color][color=#ff9933]x2[/color]
[color=#999999]i5-4200M @ 3.5Ghz [/color][color=#ff9933]turboboost[/color]
[color=#666666]N[/color][color=#999999]vidia GT720[/color][color=#ff9933]M[/color]
[color=#999999][color=#666666]1[/color] [/color][color=#ff9966]TB[/color] [color=#999999]HDD[/color]
[color=#666666]Windows[/color] [color=#ff9933]8.1[/color]
[color=#999999][color=#666666]Wii [/color]Pro Controller [/color][color=#ff9933]+[/color] [color=#999999]Mayflash adapter, Wii Mote [/color][color=#ff9933]x2[/color]