Why are bank transactions and cheques so slow since they were computerised?

My mother keeps saying that everything used to go faster before the transactions and cheques were computerised, so the technology itself must to blame, when I know that the computers can do whatever the people did before much faster but I don't know exactly why it's so slow so I can't really argue, and she won't listen otherwise, so why does it take so long to cash a cheque or transfer money now?