Disclaimer: These tests are made a few weeks back, so, they were done before v1.0.0 dropped on ClassicPress 1.0.0-beta2 and WordPress 5.0.2.
ClassicPress came out on top in terms of performance. WordPress was only beaten by a very slim margin, and did even rank higher on a few scores.
After optimization, both domains reflected the same trend: ClassicPress ranked slightly better than WordPress. But, again, only ever so slightly.
So, yes, it appears to be true: ClassicPress is a tiny bit faster than WordPress.