Are you using an x86 or an SPARC box?

The SPARC architecture is not very good for encryption, and if you use gcc to compile perl and its modules it is even worse, using the compiler from Sun could significantly increment your code performance.

If you are transferring the same 60 files to 30 machines, it is like encrypting 1800 files. You can use GPG to encrypt the files just once and then send them over unencrypted FTP, HTTP or SMTP connections. That would probably reduce the CPU requirements an order of magnitude.

You can also try Net::SFTP::Foreign, it is usually faster than the alternatives, though in that particular case, where the CPU is the bottleneck I am not sure...

Finally, there is lftp, a sophisticated multiprotocol (ftp, sftp, http, etc.) file transfer client. It can handle a high number of transfers in parallel and is scriptable. You can write an script for it from perl and then invoke it as an external program.