Long delay when scrolling in ListGrid

When I use the mouse wheel to scroll in a ListGrid, it takes about a second to show the new data, which is rather annoying. I notice this also when scrolling through the Reference Docs. Is this caused by the rendering? Is there a delay anyway? Or is the data fetched slow?

I already looked into the properties ScrollRedrawDelay and ScrollWheelRedrawDelay. I lowered those values to about 50ms but that doesn't seem to make a noticeable difference.

Is it possible to speed things up?