Re: [LAU] CPUs for low latency

Len Ovens <len@email-addr-hidden> writes:

> The idea of what latency is good enough for audio work has changed
> with the change from mostly PCI cards to USB. Where 64/2 was the
> normal maximum, 128/2 or even 256/2 have become common... and seem to
> be accepted as "OK". (there are also USB cards that will run at 32/2
> or better) Maybe there are other reasons for the change in thought on
> this too.

Yeah, I've noticed that. If you look at this list just a few years ago,
USB was considered "avoid like the bubonic plague." The best option was
PCI(E), from RME if you could, with M-Audio Delta-1010 as a nice second.
If you couldn't do that, you went firewire, which didn't have as good
latency/bandwidth as PCI, but it was pretty good, and the only issues
were that FreeBob (now FFADO) was pretty beta at the time. You were
only advised to go USB if you were a masochist. Even Windows users
couldn't get it to work right.

Now, we're all singing the praises of USB. Could that be because there
are no longer a lot of PCI or firewire interfaces being made? Seems
like sour grapes logic -- "I can't get those nice PCI/firewire
interfaces anymore, so maybe they weren't so nice after all..."

I'm sure at least part of it has to do with the enhanced bandwidth of
USB 3, but is it any better for latency? Do the gains translate into
acceptable performance on Linux? If we're scaling back our expectations
in terms of real Jack settings, then it doesn't seem so. How does it
compare with a nice PCI card? So far, all I've been seeing seems to be
that since USB 3 is now all we have, it's great and wonderful, because
it just is. (And since it's now all we've got, it had better be.)

-- 
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-- Keycorner --	+	sites, computers are making people
-- Recording --	+	easier to use every day."
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