I have 2x 256Mb Crucial C300 SSD's operating in RAID0 in my new 17" i5 MBP. The array has a sequential read speed of around ~345 MB/s. But when I attach a Firewire 800 device, the read speed increases over 50% to ~525 MB/s!!! Write speeds increase less but still go from 385 MB/s to 425 MB/s! The speed-up is substantial even on small, random reads and writes too. It is so significant it can even be 'felt', albeit subtly, in regular system use. This problem has been written about by Lloyd Chambers of macperformanceguide.com using different drives in RAID and in an i7 MBP. You can read about his findings here: http://macperformanceguide.com/Reviews-MacBookProCore_i7-SATA-Bizarre.html Mark Coughlan writes about the same thing except without the RAID configuration and using a regular HDD in the optical bay: http://www.markc.me.uk/MarkC/Blog/Entries/2010/6/17_2010_Macbook_Pro_i7_-_Weird_SSD_Performance.html My question is: does anybody have a solution to this aside from always attaching a Firewire device? Assuming its not an electrical thing, is it possible to 'trick' the system into thinking a device is attached to the Firewire port through software? Can a file be written or 'mounted' in /dev to give that effect? Otherwise, is there something I can do in hardware? I never use Firewire for anything so I am happy to lose the port functionality if necessary.