what you're hearing is latency. the signal you're hearing has to go through an analog to digital stage, be processed by the software, and then be rerouted back through a digital to analog stage so you can hear it.
the 1st and 3rd stages are not instantaneous and, for a particular setup, those values are fixed. the software stage can be made longer by adding plugs at record time.
so while a faster machine may help with the middle bit, you're still going to get latency. as recommended, you should record without plugs to minimize the latency, but you won't eliminate it so long as you're monitoring as you are.
there are other options, such as monitoring your analog signal before it hits the converters. there are a number of ways of doing that, the most basic being a y-cable, and the rest being further implementations of a y-cable (half-normal patch bay, split through a mixer, etc.).