Installing too many apps+games on an Android device makes it slower.is it the case with Windows Phone 8 also.?

[Vinay S Choudannanavar]

So i have experienced that my android devices get a bit slower when i install to many games and apps onto it...then what about Windows Phone 8(over a Lumia 520)..is it the same case..? And is it true that no ANTI-VIRUS software is needed for a Windows Phone 8...?