All the great golfers are able to swing each and every club with a consistent tempo and great balance. Rhythm and balance are inextricably linked. Some golfers have a fast tempo, while some have a slower golf swing tempo but still remain balanced.
The speed of the tempo is irrelevant, it can be slow or fast, but what matters is the consistency and the smoothness of it. Some take a metronome with them when they practice, whilst others go with whatever the latest gadget on the market is that has been designed to help.
The main problem with any golf swing is that the golfer tries swinging too hard and too fast. This might seem a bold thing to say, but it applies to all golfers at some point. The main reason that they do swing too hard or too fast is that the faster your swing then the greater the power you strike the ball with, and hopefully the greater the distance it will go. Though this is true in most cases there is no need to be at maximum speed for the whole swing, only at the moment the club face comes into contact with the ball.
Think about it, you could be swinging in slow motion for your entire back-swing. And you can continue swinging in slow motion for the beginning of your downswing. The only time you need be at full speed is right at the moment of impact with the ball.
So thinking of what you need to achieve, hitting the golf ball as your club reaches the required speed, then you have about 99% of the swing to work on. Obviously you cannot just switch the power on at the end of your down-swing, there has to be a gradual acceleration. If the acceleration is hard, and not smooth, you will become unbalanced and accuracy will be lost as the club face comes into contact with the ball.
Have you ever studied the swing of a top golf player, it appears effortless. They have such a good tempo to their swing the whole process seems smooth and under control. The club speed at impact is exactly right and no effort has been wasted with an over-swing.
The best way to get the tempo of your swing sorted out is to go down to your local range and hit a few balls. Do not worry where they end up, just concentrate on getting a smooth and balanced swing. Then you can think about the mechanics of getting the golf ball to go where you want it to go.