I use artlantis for rendering and have not really noticed a huge difference. but a major increase in performance in AC9 generally, the only drawback is you can't have multiple programs operating at the same time.
If you are using AC9 for rendering then switching off hypertreading wont make any difference, as AC9 supports dual processors for rendering already.
Hope this helps
Cheers Nuge
AC27 i9 11900K / 128G ram / GTX 3090 / D5 Render