Firewire latency

J

Jamie Jukosky

New member
A couple people in a few posts asked whether there was any unusual latency associated with firewire. I can't claim to be a computer expert but with Sonar and my MOTU 828. I get can get down to 2.2 ms of latency. This is on an ECS K75SA motherboard with 256 MB ddr, athlon XP 1500, and a 30 gig Maxtor 7200 rpm ATA hard drive. It works great! For laptops, all I have to say is recording without a 7200 rpm hard drive sucks.
 
What kind of real life latency do you see though? I can get down into the <5ms range too if I just record or playback one single track. Can you get 2.2ms while working on a full-sized project?

Slackmaster 2000
 
There used to be a lot more latency associated with firewire, but at this point I'm sure it's comparable or better than PCI/ATA. The first few generations of firewire chipsets were atrocious. I tried 5 or 6 different drives out in a Mac Pro Tools system, and most of the time I was unable to get a single audio track to play or record. However, once the Oxford 911 firewire controller chipset (now the defacto standard I believe) was introduced, most of these problems have dispappeared, and I think most people will get equal or better performance from a drive connected over firewire than from a drive connected over ATA.
 
ATA uses a much more limited bandwidth than firewire. 33MB/s compared to 400 MB/s. Neither of these devices will ever realistically reach either of these thresholds, but the bigger "pipe" of firewire allows higher burst rates and higher sustained rates.
 
Huh???

ATA133 is already available - thats 133Mbytes/sec for IDE. Firewire is stuck at 400 MEGABITS/sec not BYTES (thats 50Mbytes/sec -> 400/8=50; there's 8 bits in one byte) and that is only possible if the Firewire HD is the only device using the Firewire bus at any time. Like USB, the total bandwidth is shared among all connected devices.
 
Ah, you are correct, sir. I don't have ATA 133 or any ATA 133 drives, so I haven;t paid much attention to it. And I always forget the MB / Mb thing, because I'm just dumb.

I recently used an external firewire drive on a Mac with some drivers made by a company called DAM, and we got better performance with the drive in a firewire enclosure than we did on the internal IDE bus (where the drive started out). It was hiccuping on a 64-track Pro Tools TDM session when it hit a point that had some dense edits, so we pulled it out and stuck it in the firewire enclosure and it worked just fine. Then again, it was a Mac, and probably had ATA-66 or something.
 
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