I think @WA mentioned the 50 shaders aren't all 100% active, only one working at a time.
All of the shaders are RUNNING simultaneously.
But because of the Timer code
only two are ever Generating a Display, the rest are transparent.
So this reduces the Load on the GPU as it only has to Show, one shader at a time, or Two during the Transition.
But it is still doing the calculating for all 50 shaders at the same time..