cpu not even reach 20% .......(if cpu not reaching 20% that doesn't mean it's slow.. feed the processor & watch) what u r doing with ur pc? run something that taxes ur processor and then watch how it will go above 20%... if ur pc is ideal then ur cpu will not go beyond 3 %...
Cool rig setup, not-so-cool understanding. A lower load is always good. Do you want push your CPU to the 100% limit at all times? That would be like riding a horse at its max speed for hours. In the end, the horse could die of exhaustion. Well, it's not like your CPU could die like the horse, but it will raise the temperature significantly. Which without proper cooling, can literally kill the CPU.
A 20% load means that the CPU is only using 1/5 of its total processing strength. Imagine if the CPU is at 80% load while only watching HD video. Now that sucks
If you want a faster response from your PC, tweak the OS. Although, I don't think with an i5 and 4GBs of RAM will need any OS tweaks.