True, but the amount of data being written is so small it shouldn't be stressing the disk at all, and it shouldn't effect the processor usage either. Plus, the data is being rendered to the RAM first, and then to the disk later. If the total image size is 4MB, and it takes a full minute to render, that's 68k/second of data that's coming out. Modern hard drives have read/write speeds of at least 50MB/sec, so I doubt that the hard drive is a bottleneck here. But then again, could be, can;t tell for sure :)