Page faults don't have anything to do with CPU cache but with your RAM. https://en.wikipedia.org/wiki/Page_fault I'd be curious what kind of results you'd get if you'd set your virtual memory's size to 0 (assuming you can close enough background applications for RAM size not to become an issue).
Yes, not all vertex data is buffered. The difference between the default skin and custom skins you are noticing are the small, blue, particles appearing with every hit. We do plan on buffering these. We are currently rewriting a huge portion of the rendering infrastructure to allow for easier optimizations like that in the future.
What kind of CPU do you have? I haven't heard of anyone where the CPU would be the bottleneck. Even without vertex buffering osu! just doesn't have many vertices in the first place. I am baffled that you are getting CPU capped at all.
Yes, not all vertex data is buffered. The difference between the default skin and custom skins you are noticing are the small, blue, particles appearing with every hit. We do plan on buffering these. We are currently rewriting a huge portion of the rendering infrastructure to allow for easier optimizations like that in the future.
What kind of CPU do you have? I haven't heard of anyone where the CPU would be the bottleneck. Even without vertex buffering osu! just doesn't have many vertices in the first place. I am baffled that you are getting CPU capped at all.