I've encountered a weird bug with Iris based shaders where I get immense lag while in a GUI or any menu
I've experienced this bug across multiple shaderpacks (Photon, SEUS_PTGI, Compl Reimagined)
I'v experienced this bug in large Forge modpack (300+ mods) with Oculus AS WELL AS with a super light client side Fabric pack (10 mods)
In both cases I've tested the modpacks on separate computers and it only occurs on one of them (my main pc)
I've seen a few other unresolved posts with this issue and was hoping to add my input