NVIDIA Users and < 6.3 ROCm users can expect up to 1.5x performance for ssimu2 with this update. Butter also improved but marginally.
It is now also possible to have a different number of stream used inside vship (which control VRAM consumption) than the number of vapoursynth threads (used for decoding). You can use the option "numStream" to set that.
(In general, stream managment was improved but it is pretty much invisible to the user)
Have a nice time computing your favorite metrics!