Tip: use Gallium Nine for a big performance boost if you're using Mesa. You need to use d3d8to9 or something and override d3d8.dll and d3d9.dll (for example the ENB mod provides both of these).
Also tried using d9vk but couldn't get it to work. Anyone else have experience with using it?
For example VH ep2 multimode Rag Rappy should give 93 xp but it gives 120 (with the current 2x boost it should be 186 but is 240). This is approximately 1.3 times more. Happens both in purist and non-purist mode. Only ep2 seems to be affected by I didn't test extensively.