The MOTU 2408 consists of a PCIe (or you can order it with a PCIX) card and a breakout box connected to the card with a Firewire cable. However, the fact that it is a Firewire cable does not mean that it is making use of the computer's Firewire circuitry. MOTU has just announced a new version of its 828 Firewire interface that comes with new features and new software - - which may imply that their PCIe interfaces will be similarly updated, you might want to wait a little to see if this proves true.
If you want the "fastest" possible card with the lowest latency - - and price is no problem - - you might want to check out Apogee's offerings. Their Symphony card reputedly has the lowest latency available but requires one of their proprietary D/A or AD/DA boxes. These are VERY pricey items: the Symphony card is about $720, the Rosetta AD/DA 8 channel converter is about $2700 + $190 for the requisite Apogee X-Symphony card to connect it to the Symphony, the DA-16X, 16 channel digital to analog converter is about $3200 (+ $190 for the requisite Apogee X-Symphony card - - for A/D conversion you would additionally need an AD-16X box at the same price as the DA - 16X box). To control volume from these output devices it appears you would need a mixer or something like the Dangerous Music D Box Summing/Monitoring system (beginning at $1400). I've heard this stuff and it sounded great, but . . . . it does cost about $5000 to duplicate the features of the MOTU 2408 which costs less than $1000.
