Every configuration will have a specific slot order. Your Pro Tools system should come with a booklet entitled, Pro Tools Expanded System Guide. In this document you will find the specific slot order for your system.Slots in the computer: there is no general rule for the slot order of the host card in the computer (sometimes it goes in the lowest slot, sometimes in the middle, and sometimes at the highest numbered slot). Additionally, other cards may have to be installed in the computer, such as a supported SCSI card, or a video capture card. Slots in the expansion chasis: for Digidesign cards in the expansion chassis, the general order to follow (from lowerst to highest slot number) is, Mix Core, Mix Farms, d24s, Mix I/Os, DSP Farm II's*, DSP Farm I's*, and Sample Cell II's (TDM or non-TDM). Here are a two examples, using common configurations: A Pro Tools Mix Plus system, with added Mix cards, DSP Farms and Sample Cell cards: 13 Slot expansion ChassisSlot 6: Mix CoreSlot 7: Mix FarmSlot 8: Mix FarmSlot 9: Mix I/OSlot 10: DSP Farm IISlot 11: DSP Farm IISlot 12: DSP Farm ISlot 13: Sample Cell II TDMSlot 14: Sample Cell II TDMSlot 15: Sample Cell II TDMSlot 16: EmptySlot 17: EmptySlot 18: Empty A Pro Tools 24 system (using a d24 card as the core), with Mix Farms (no Mix Core), and Sample Cell cards: 7 Slot expansion ChassisSlot 6: Mix FarmSlot 7: Mix FarmSlot 8: d24Slot 9: DSP Farm IISlot 10: DSP Farm IISlot 11: DSP Farm ISlot 12: Sample Cell II TDM * DSP Farm I is the original PCI DSP Farm (serial number starts with the letters "FF"); and DSP Farm II is similar to the original DSP Farm PCI, except that it went through a manufacturing revision (serial numbers start with "FG"). Both cards are functionally identical and perform exactly the same. The only difference is that some DSP Farm I's may need an upgrade of one of the chips in order to work in newer computer models or expansion chassis. If you have a DSP Farm I and are unsure of wether you need the upgrade, consult the Digidesign Technical Support department.