FireWire 400/800 {DO THEY ALL SHARE THE SAME BUS?}

Unless this is recently changed, I believe you will find that both the Macbook Pro and the current imac all share the same firewire bus for both the FW 400 and 800 ports. This has been discussed extensively in the past. In my usage, I have found that if you connect anything to the firewire 400 port, the entire FW bus runs at firewire 400 speed. The only way to get Firewire 800 speed from your drives is to plug any FW 400 devices into a drive that has both FW 400 and 800 ports, and plug the FW 800 drive only into your Mac. You can verify these settings in System Profiler. This also applies to any Express cards you may plug into your Macbook Pro, which also still operate off the same Firewire bus as the internal ports.

I have plugged my MOTU Traveler (FW 400) interface into an OWC FW 800/400 drive with no problems, and the drive does operate at FW 800 transfer speed. The imac does not have any expansion ports.

Don't know how many audio tracks you are planning to record at a time, but I wouldn't worry too much about FW bandwidth. Your main concerns regarding audio are hard drive speed and RAM. Get as much RAM as you can, and record to an external FW 800 drive. You should be fine.

Bob

Hi,

here is the Developer note of the new iMac with a nice block diagram:
http://developer.apple.com/documentation/HardwareDrivers/Conceptual/iMac_0708/in dex.html

As of now all Intel-Macs (even the Mac Pro) have only one FireWire-Bus.

regards

Stefan

Fortuny wrote:
Hi,

here is the Developer note of the new iMac with a nice block diagram:
http://developer.apple.com/documentation/HardwareDrivers/Conceptual/iMac_0708/in dex.html

Thanks, great find. Here's the note for white C2Ds -- and the master index for others:

http://developer.apple.com/documentation/HardwareDrivers/Conceptual/iMac0609SuperDrive/index.html

http://developer.apple.com/documentation/HardwareDrivers/AppleHardware-date.html #//apple_ref/doc/uid/TP30000440-TP40003576-TP30000519

Looby

Hi,

Different interface manufacturers seem to take slightly different views as to the best options. M-Audio have recommended having the drive on the opposite side of the interface (computer>interface>drive). I will check tomorrow, but on this Alu iMac, when I did have an M-Audio Firewire 410 connected to the computer Firewire 400 and a LaCie d2 connected Firewire 800, the LaCie seemed faster than when connected FW400. I will also try it chained off the HD.

Karn.