As you can see from the table above, the approximate probability of getting a winning hand in any given round is 45.456%. The return rate when placing five credit bets is 99.543% whereas when placing a one to four credit bet it is 98.181%, translating to house edges of 0.457% and 1.819% respectively.
Whether you play fast or slow makes no difference to the payout. But since all slot machines pay out less than is played over the long run, the more you play the more you lose.