you should leave vertical synchro of the driver to “application controlled” then vvvv will deal with it. if you set presentation interval to “default” or “waitforframe” each frame will wait for the vertical sync.
preparegraph and resetcache are cpu times used by vvvv.
present is gpu time for “presenting” the frame to the frontbuffer.
square textures should in general be faster. but i’d say not always. copying an 800x600 video to a 1024x1024 square texture may be slower then copying to a 800x600 texture…maybe depends on what happens further with the texture…
so yes. square videos maybe better. but that is only valid for filestream then because videoin won’t give you cool square videos unless the driver does a cropping there.
hm…if you say cpu is at 50%…do you have a hyperthreading cpu? if not can you try on a hyperthreaded cpu? could bring some more advantage for your setup.