I have a QGraphicsScene with some items that inherit QGraphicsPixmapItem, and change their displayed pixmap at the advance() function.

Even though QGraphicsScene is supposed to have a very good performance with a million items, 20*15 of my items at size 32px*32px at 25 fps generates 95% CPU usage (CPU is an AMD Athlon XP 2200+). 40*30 if these items with 16px*16px size make 100% CPU usage, and lag.

What should I do to have reasonable performance?