Slow scrolling of a listview in QListView::IconMode using QAbstractItemView::ScrollPerItem

So this is my listwidget that has items with thumbnails:

http://i.imgur.com/mulcrmk.png

when i try to scroll with my mouse, it scrolls one pixel per scroll. This only happens on Windows, on Ubuntu it scrolls one item per scroll. With the same source files

And if i change Scroll per pixel->scroll per item, its the same, scrolls per pixel