Few fat models vs. many slim models in CodeIgniter

Question

Any difference, performance-wise?

Answer 1

It's too situation dependent to give a canonical answer. With fat models PHP will be compiling a larger class to opt-code on each request cycle, much of which it doesn't need. With many thin models PHP will need to instantiate more classes at run-time for your application to work. Each could become a theoretical performance bottleneck under different situations (although your actual database connection will become a problem long before that).