forgot to mention about torque also. Lower gear = more torque.
Aiya, I'm not too good in explanation, but I'd try.
This is in a real-life scenario, not sure if it works the same in a
game.
Say both cars start together. Auto cars usually set to change gear
at 3000 rpm, so when the needle reach 3, it changes gear
automatically, causing a drop in speed, and also drop in engine rev
(rpm).
Manual cars, it's up to u when to change gears, so if I'm racing,
I'll rev up high. When the auto car already change gear and drops
in speed, I still in gear 1 and flooring my accelerator, speed
still going up. This is the part where I start to overtake the auto
car. That's why manual pick up always win auto (talking about same
make).
Untill what rpm is very dependant on the car. There's different
optimum rpm vs performance for different cars. Some cars maybe only
6000rpm is best performance, dragging more (rev higher rpm) also no
use - no more power for higher speed. Most are higher than 6000 for
optimum. If u watch Initial D anime, Takumi later got a new engine
for his AE86 which is a very high rev type, and the performance is
best at 11k rpm, that's why he always rev it to 11k.
hard to explain lah. gotta try then u understand ba.