I have the x800 which you can easily overclock a bit, to match the x850 — making it equivalent to the fastest ATI card you can get in an AGP mac. However, if you can get your hands on a (now discontinued) nVidia 6800 Ultra DDL (and you can spare the PCI slot next to your AGP slot, as it takes up that space with its cooling assembly), it might be a bit better with Motion, as the nVidia cards apparently do not have the 2048×2048 layer size limitation when working in Motion that the ATI cards do. It seems nVidia cards can handle 4096×4096 layers…from what I’ve read elsewhere on this board. Too bad I figured that out after I bought my x800. Oh well, otherwise the ATI is great and probably cheaper than the nVidia in any case.