is it more you invest the fasteer you would get paid back??
The more you invest the greater your chance to get paid a 49% share of new deposits. The system randomly selects a member who receives 49% of a new deposit, its selection is linearly weighted based upon the value of your investment. In other words, the bigger your investment the greater your chance to receive payouts.
You can always add more to your current investment by depositing to the same address as your initial deposit to increase your chances.
For instance, I am member #115 and I deposited a total of 0.7 btc. I've been receiving 10 payouts already and have made 0.24 btc profit so far because the size of my deposit gives me a very good chance to get picked by the system more for new payouts. The main reason for this is because there's only one other member with a bigger deposit than me right now so I hardly got any competition. Ofcourse all of this would change if other people start depositing bigger deposits too, then more payouts would go to them.