Does anyone know if i will be able to use a firewire mixer (im looking at the Mackie ONYX line) w a 400mbps firewire connection or do they generally require an 800?

Also any feedback or experiencethat would help me to choose a mixer to go with would help me alot.
Yep, you'll be able to use it, but obviously the transfer rate won't be as fast. You may run into problems with latency etc when recording multiple tracks.
DARK_MATTER, Instrumental Post-Metal from Ireland

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Just as a heads up, the Mackie ONYX line is terrible when it comes to setting it up for use for recording. We use one for practice (the 1640i) and it seems like my guitar player is constantly re-installing the drivers to get it running. Hes running a Mac and Cubase so its not like hes running it on old technology.

Are you sure you need a mixer or do you really need an interface?
Derpy Derp Derp Herp Derp
Hi there!

I'm using the Mackie 1640i to record my album now, and since I set it up I had no problem. So I was able to record 16 tracks in stream with no clipping or noises. Here is what I would try (it worked for me using SONAR):
1.disable the read/write cache option in your DAW.
2. Disable all sound devices on the computer other than the mixer.
3. Disable antivirus and internet connection while working.
4. Driver in ASIO mode (Mackie driver)
5. Be shure you got the last driver (not the one they give you with the mixer)
6. The low latency also depends on components, on how they are connected in the computer and set up. I did a research myself on how to set up the hardware connections but it gets very complicated.

It is a frequent issues to struggle for a low latency on laptops that are not built or set up for recording music. Anyway I use a laptop with a Express Card where I connect my firewire cable at 400 mbps and I have no problems. But if you can have a firewire connection directly on your computer you should be sure that the internal card is not so old. Old hardware can cause many issues.