Factoring with programs such as ECMX is quite fast. It can find factors with the number of digits in the low-20s fairly easily, mid-20s somewhat less easily, and upper-20s with lower chance of success. It has found a 30-digit factor. (Finding factors with the elliptic curve method is always chancy for larger factors. The greater the number of curves that are tested the greater the chances of success, but the number needed (on average, one can sometimes get lucky or unlucky) increases rapidly with the size of factors. It is always best to use the fastest machine available. ECMX uses the accepted standards for limits of when to stop working with one curve and switch to the next. It has preliminary primality testing, finding small factors, and powers.