The fact that just enabling exceptions adds a non-zero cost to the runtime of your program, even if the code itself does not use them, means that they are slower than just checking the return values. I've seen values from 5% to 15% slower runtime performance for just enabling exceptions and not even using them. I don't think removing the error checks will give you back those percentages.
The problem with proving something like this is you have to build and maintain two separate sets of code for the same project, one that uses exceptions in the correct manner, and another which does error checking to the same degree. Nobody has time to do that for a significant project.
The problem with proving something like this is you have to build and maintain two separate sets of code for the same project, one that uses exceptions in the correct manner, and another which does error checking to the same degree. Nobody has time to do that for a significant project.