Doubt: step transition(Model) - Urgent

Hi All

I have some doubts in step transition in model:

We have flow step which splits into three transitions. We have placed condition in first two transitions so that at rum time it will first check the condition and then only execute the next flow step but there is no condition for third one and we are checking the condition in the next flow step only for the same.

So my question:
1.How many thread will be created at run time if it satisfies first transition condition?
2.At run time, will it always create a new thread for third transition and executes it irrespective whether it satisfies condition for others two?

3.Will there be any performance issue due to this, if we do/don’t place condition for third transition?

I am looking for any response desperately.