[Ti] no FW800

[Chris Olson]

On Jan 10, 2006, at 6:34 PM, John Griffin wrote:

> Now there is an excellent question! With my Powerbook 1.5mhz I ran  
> benchmarks on a LaCie “Big Disk” that has both FW800 and FW400.  
> There was very little if any difference in the speed between the  
> two interfaces. Perhaps it makes a difference on a Quad Powermac,  
> but I doubt if it has much difference on anything else.

Actually very wrong.  Buy something other than a LaCie if you want a  
decent drive.

The limiting factor here isn't the bus bandwidth, it's the drive(s)  
used in the LaCie Big Disk.  They're on a EIDE controller, therefore  
can't deliver Firewire 800 I/O.  You've saturated the bandwidth of  
the disk controller.

To keep up with Firewire 800 you need a hard disk that can deliver  
sustained 100 MB/sec I/O speed.  The only thing that comes close is  
SCSI or SATA.  With a hard disk that can deliver FW800 I/O a true  
benchmark has to deliver data over the interconnect from RAM to  
disk.  Transferring from disk to disk will always be throttled by the  
I/O bandwidth of the slowest disk, and FW800 far exceeds the I/O  
capability of EIDE disks.

-- 
Chris

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