There are various options available to maximise the speed of CM03-04, many of these are blatantly obvious but please bear with me.
(1) Select fewer leagues
Each league you select requires processing to update, selecting fewer will make the game faster.
(2) Don't have active leagues are 'full detail'
Full Detail leagues take much longer to process matches then non-full detail leagues.
The only visible difference to a user between the two is the fact that you can't watch matches from non-full detail leagues in 2D.
NB. If your main league is non-full detail then all competitions your team is active within will still be simulated in 'full detail', however competitions your team isn't active within won't.
(3) Drop the database size down
The more players active in the game the slower it is, hence dropping the database size will increase the game speed considerably.
The largest effect for this is when you drop down from 'large' database size - as this has around 3-4x more players than the medium database size setting.
(4) Turning off virus checkers
Some virus checkers analyse files when they are modified this can slow down game processing considerably.
NB. You can normally just ask the virus checker to ignore specific directories (ie. the CM one) rather than turn it off totally, this is recommended.