Follow up to Jan's finding here : #2533 (comment)
With setDTthreads(1) he found a performance drop with 1.12.0 :

• 8 groups

7.7s is now 12.8s
9.8s is now 15.8s

• 1e6 groups

6s is now 12.4s
7.6s is now 17.6s