Play Framework how is threading handled when you have many blocking requests

[herbe...@gmail.com]

This is my first post, I am database administrator and looking to use play framework version 2.4 . I have read the play 2 documentation and still have a few questions since I am very new to it. I have a messaging system that will need to handle loads of up to 50,000 blocking threads per second. If I am correct the maximum number of threads available on play are as follows:

Parallism-Factor * AvailableProcessors

Where the Parallism-Factor is the amount of threads that could be used per core? I have seen that most examples have this number as 1.0 what is wrong with going for a 100 or so? I have this P-Factor right now set at 10.0 and I have 150 cpu cores so that means that I have a maximum of 1,500 threads available if that is the case and I have to process up to 50,000 blocking requests per second then the system would be very slow right? so that the only way to scale would be to add more cores since all the requests are blocking?