Dave Plowman (News) wrote :-

SDS tends to be far kinder on the bits than hammer. It's the heat that
kills them.

Years ago I had a B&D drill that had a switch for the 2 speeds, 3300 and
2800 iirc both far too fast for masonry drill bits, it used to burn 'em out
rapidly.
I had a very frustrating time fitting a 4" fan in quite hard bricks.
Slow, 900 rpm is the answer or better still SDS

Regards Jeff