I applied the acs patch on 4.7.5 and on 4.8.12 as well. Both times, there were no errors, but when I execute
find /sys/kernel/iommu_groups/ -type l
the groups stay the same. I still got both graphic cards in group 1. When I try to start the windows vm, I get an error saying "group 1 is not viable, please ensure all devices within the iommu_group are bound to their vfio bus driver"
Edit: Found it, booted the wrong kernel