Yes, it will run more slowly. Buffering is an optimization. It's almost always a good thing.

If you really need to send data as soon as possible (because the time it takes to generate the data is much longer than the time you lose waiting to send optimally-sized network packets with all of the overhead and latency there), disabling buffering at the right place and for the right amount of time is a worthwhile tradeoff.

Don't make the mistake too many people here do, though, in thinking that buffering is always a problem. It's not. It's on for very good reasons. They don't always apply, but it helps far more often than it hurts, in my experience.

Disabling buffering globally by default is a code smell, in my opinion.