> Orren and Ivan > > i've followed this discussion in and out, but i wanted to add that i > have done extensive > drive testing with logic and have never seen RAID improve > performance. i've got a dual G5 > and have tried every combination of drives from a RAID made up of 8 > 15K SCSI drives > attached to an ATTO UL4d (4 drives per channel - read and write times > around 270 MB/ > sec) to a firewire 400 drive. and this is what i've seen: > > 1. RAID does not improve performance with logic. when using a RAID > with logic, i've > always gotten the same performance as using a single drive from that > RAID. meaning, the > 8 drive 15K SCSI RAID performed audio playback at the same level as a > single 15K scsi > drive. so if ivan is getting 90 looped tracks to playback from his > RAID, my guess is he > would get that exact same performance from 1 of the drives which make > up the RAID. > > 2. Logic on X can not make use of multiple drives for playing back > audio. well, i should > say - it can playback audio from multiple drives, but it doesn't > improve track count > performance to do so. meaning - if you can play back 50 tracks from > 1 drive and you add > a second drive just like it, you will still only be able to playback > 50 tracks (even if you split > the tracks evenly across both drives). > > 3. if you think Logic playback performance is bad at 44.1, try it at > 96K - it degrades > dramatically at higher sample rates. and i'm not talking about being > able to play 1/2 the > tracks at 88.2 as 44.1 - i'm talking about being able to play about > 30% of the tracks at > 88.2 that you can at 44.1. > > 4. Logic exhibits the same lack of performance improvement when > using multiple drives > with the EXS for streaming samples - you can stream from multiple > drives but it does not > improve performance. meaning, i experience dropped data at the same > point in songs > whether streaming from 1 scsi drive (all instruments on 1 drive) or > from 8 (with the > instruments spread out across the 8 drives). > Well, You are absolutely WRONG on every point except #3(...yes,96k does impeed performance). I've had years of experience with this, and what I've found is this... 45 tracks on an interanl ATA will playback fine. 90 tracks on the internal ATA will stop the system... ie...core audio error message. I can take half the 90 tracs and put them on the OTHER internal ATA and all 90 playback as easy as the single drive playing 45 tracs. The same 90 on a SCSI array playback even easier with no probs. With slower drives it is quite easy to watch the audio performance meter turning red as well as just listening for problems and watching the computer stop playback trying to crunch data. This not only was the case with the Dual 2 gig, but easily quantifiable on the dual 800 I have when I went from internal drives to an internal 160 SCSI with one 15k Cheetah way back on Logic 4. I've mixed a lot of records on these systems, and drive speed is THE difference between success and utter frustration. By the way, I'm talking about actual full song length 44.1 24 bit wave, or SDII files in the arrange window. The setup is a dual 2 gig G5 with 2 gig of RAM. 2 internal 250 gig serial ATA's, a 72 gig SCSI array thru an ATTO UL4D, an RME digi card playing back thru an Apogee AD 8000. Drive speed is THE difference. Regards, Ivan