Live Software - Interface Latencies & Multi vs. Single Core Host Latencies

[jufros]

I'm putting together a live software synth rig at the moment using my Macbook Pro 2.4ghz Intel Cuo Core w/ 4 GB RAM. The backbone of the VSTi synth "rack" will be composed of Native Instruments Komplete 6 and Korg Legacy Collection sounds. I have some hardware and software questions about implementing and optimizing the setup.

1) How severe of a difference will I see in stage latency with different firewire interfaces?

I currently own a Presonus Firestudio Mobile Firewire interface. I won't be using the preamps and I'm pretty satisfied with the converters. I am a serious player though and I'm wondering about the relative latency differences I'd be expected to have on stage in my situation with different interfaces. I am very serious about getting my latency to an acceptable margin. For this setup, it's considerably more important than the live sound quality.

While I'm more interested in latency differences between interfaces in the sub $1k price range, I'm not necessarily opposed to forking over for an RME Fireface either. The FF800 would be a significant stretch at the moment but the FF400 would be much less so. Roughly how much faster would my latency be with one of these? Are the latency figures for the 400 and 800 comparable?

2) How does your host's multi vs. single core utilization affect latency?

I'm looking at Logic's Main Stage 2 and NI's Kore 2. They'll both do what I want but Main Stage has multicore support while Kore utilizes a single processor's resources. I've heard that Kore will therefore offer lower latency at the obvious processing headroom cost. Is this true and how significant is this difference going to be?

[synthoid]

well, I can't answer most of your questions. But I do use a FF400 on stage with a new Macbook Pro, and I run Ableton Live with 32 samples of latency. Sometimes with 64 samples of latency. It depends on how nervous I'm feeling after the soundcheck . I love the FF400 for this job because
1) it is small
2) it is reliable (well, there's a nasty bug with the MacOSX 10.6 driver for it, but generally speaking the RME stuff is solid)
3) it is bus powered! I didn't think about that when I chose the unit, but it gives you a kind of UPS at least as far as the audio interface is concerned, and that's a good thing.
4) it has some extra preamp inputs and a headphone output on the front panel. this is really nice for last-minute extra inputs, or for getting an extra copy of a cue mix if you're doing that using TotalMix

hth,

-synthoid