Finally got a chance to look at this. I see that every attempt to render the map is aborted in under a second. Per chance, are you using GPS for a position source and have enabled auto-centering the map? A Celeron processor is pretty slow (you didn't mention what you were using for a disk drive), so if you are constantly moving the map, the render for the old center location would be aborted (never displayed in the map window) and a new render would be started. This would be exceptionally bad if you are zoomed in very close, as almost any motion (including noise in your GPS receiver) would be large enough to force an abort and re-render.
Andrew, KA2DDO
author of YAAC
