surroundguy is right,,, but also with all them cards you explain you have,, will you be using ANY other PCI card? (like SCSI card or something?) Because keep in mind a G4 has 4 open PCI slots.. So if you are using a SCSI card for extra drives, or ANY other type of PCI card for something,,, then you will only have 3 open PCI slots on the G4,, then you will have to get a Expansion Chassis, because you said you are using a Mix core with 3 extra Farm cards correct??. As a matter of fact,, you said you wanted room to grow,, so you may want to get the expansion chassis anyway. And hey,, the new G5's only have 3 available PCI slots !!!! So if you go G5 one day for your HD system you said you may get one day,,,, then you will definitely need the expansion chassis. Just make sure to get one that will work for your current set up AS WELL AS the new G5 set up,, cause the new G5 has different voltage powering it's PCI slots than the G4, and the G5 CAN NOT use both,, just one, I think it is 3.5v ... BUT the G4 can use both it's native usual 5v AND 3.5v PCI cards......... Hope this helps,,,,,,,