In what way? Is it startup time for perl, or the execution speed once it's running?

AFAIK gcc has always had a reputation of making one of the better C compilers. So, I would not expect the code generated by gcc to run "slow".

Cygwin requires use of a private DLL containing a linking layer between the internal Unix-like API and the native Win32 API, but MinGW allegedly builds real native Windows programs, that don't require an external DLL either, so I would expect MinGW to perform better, or at least not worse, than Cygwin.

But those are my expectations, I do not have any benchmark data to back them up.