Android: How can I speed up the scrolling of GridView?

I have a GridView that displays images (7 columns of images that are 166dp x 249dp) that are all the same size (there are over 150 images), and I'm using the view recycling mechanism through the view holder pattern by way of an adapter. My views are all simply ImageViews. There isn't much going on that should be slowing the scrolling on this widget (there are 21 images on screen at a time), but the thing just scrolls so choppy. What can I do to speed it up?