Yes, and no.
Sometimes, manufacturers lower the clock speeds of the CPUs and/or GPU on to prevent overheating and battery drain. It's mostly seen on lower-end devices with poor cooling. This is a kernel-wide modification, and can be bypassed by editing and recompiling the kernel.
This underclock is usually around 40-70Mhz for GPUs, which doesn't actually affect the performance much. CPUs usually don't need to be underclocked.
The way a kernel sets this limit may differ, so there isn't an exact tutorial to do this.