And now being a programmer is helpful XD
Random number programs grab the milisecond time from the machine they are based on (or a centeral machine depending on the archtercure)So as much an element of randomness a program is capable of coming up with.
Sadly this is not entierly wihtout pattern. You will find a random number generator (weather the dice or the GNG) will use the same method, only with diffrent peramiters, 1-20 or 1d20 will use the same paramiters. The funny thing is that random number programs tend to favour the centeral numbers, not sure why. Just a quirk of the programs methods I'd assume.
So generating wise. Both methods are identical =3