An Early Look At Debian 9.0 Performance vs. Debian 8.8, Ubuntu 17.04, CentOS 7, Clear Linux
At least outside of the open-source graphics performance, Debian 9 is quite performant competent with using the Linux 4.9 kernel and GCC 6.3.
The Debian 9.0 performance tends to range from being around the same speed as Debian 8.8 to being noticeably faster thanks to the updated components.
Debian 9.0 even won over the competition in some tests.
As usual, Intel's Clear Linux tends to give other Linux distributions a tough competition due to its focus on delivering maximum performance.