One speed. Two routes.
A fixed penalty is a flat £100 and three points. A court fine is a slice of your weekly take-home, banded by how far over the limit you were. Set the limit, drag the speed: the likely outcome appears first, the reasoning below it.
These are the published starting points, not a prediction of any sentence. The bands are guidelines, not tramlines: magistrates weigh aggravating and mitigating factors, an early guilty plea takes up to a third off the fine, and where no reliable income is shown the court works from deemed figures.
Points carry their own arithmetic. Twelve within three years means a minimum six-month ban unless exceptional hardship is found; six within the first two years of a licence and it is revoked outright. Points count for totting for three years and sit on the record for four. Whether points or a short ban, and where inside the range the fine lands, is discretion, not arithmetic (Sentencing Council, speeding guideline).