110. Slowing down programs
     ~~~~~~~~~~~~~~~~~~~~~
Brian Smith points out that if you type ?&FE45=1:?&FE46=0 then all subsequent
programs will run super-slow. You can try this out most easily by loading in
 program, typing in the slowing-down command, and then typing LIST. To
restore normality, do the same again but with the original values in place of
1 and 0. (Obviously, you will have to find them out with PRINT?&FE45,?&FE46
before you start.)

On my Beeb they are both 14, but I think it depends on what options are
fitted. I'm not sure exactly how this works, but you are messing about with
the internal 6522 VIA timer registers. This evidently fools the computer into
spending too much time looking for interrupts, and not enough time getting on
with processing.