He picked up the speed from the ORM?
the application speed can fall, but also depends on how your code is written without an ORM.
He picked up the speed from the ORM?
no. the speed of development can greatly increase if to be able to work with her.
my personal opinion if the project was not originally hayload better ORM. the speed is greatly increased razarbotka + code becomes much easier to develop and refactor. fewer errors, more reliability, no headaches when you need something refactorit project razivaetsya easily. if the load increases, there's a lot of opportunities for optimization.
often if the load is more on reading it is necessary to cache + in narrow places where you only want to show something, you can do direct queries to the database without the ORM. but mPas only be used to change objects.
a good ORM does not bind the hands and have the ability for fine work at a lower level.
I use a couple of years doctrine2 for php, although for many years wrote the queries by hand. reluctant to return, although it can.