My understanding is that when an animation is rendered; the harddisk is hit hard - possibly try defrag/scandisk? I cant render with low mem laptop but sr3 on desktop will render but settings tried production firefly with raytrace, shadows and bucket 16 bounce 5 only. However, was a 690 frame animation and it did fine with png which I then import into flash and looked good (for flash ;-0). Havent tried avi.