Skipping when recording with external sound card

I'm trying to record through two sound cards simultaneously.  I'm using my internal card on my laptop as well as a usb external sound card.  I finally figured out how to get both to record at the same time (i'm thinking of recording my friend at an open mic and want to be able to record his vocals on a separate track) but now the track that is assigned to the external card skips about every 30 seconds or so.  I checked my ram and it's only going up to about 20% usage tops.  Is it because it's a usb sound card?  Is there anything I can do to avoid this with this setup?

My gut feeling is that no, there's not much you can do.

I'd have thought that the two soundcards will be unlikely to be referenced to internal clocks that are generated from the same clock in the machine.

Even if they were, as far as I can tell (and I really wish someone here could confirm this), lots of modern, cheap sound devices, eg HD Audio, work at an internal sample rate of 48kHz and seem to do sample rate conversion by dropping samples.

Would different devices drop samples at different places? Would this affect the lock of the app to the sample clocks? Why does nothing these days seem straightforward and just work? These are the questions.

It just might be worth trying to set the sample rate to 48kHz to see if that makes a difference.

I'm amazed that this works at all, never mind skipping - which probably has an awful lot to do with unsynchronised sound devices, as Wildduck suggests.

With AA2.0 this can only ever work with the Audition Windows Driver - ASIO simply isn't capable of coping with two devices simultaneously. If you are not already doing this, I suspect that ASIO4ALL might be the best approach - it converts WDM drivers to ASIO, and can combine more than one. But I don't see how this will solve the sync problem, so the breakups and glitches are still going to be there, I think.

Ok so I see that this is rather unconventional...so my question is how do people who know what they're doing record seperate tracks simultaneously?

Ok so I see that this is rather unconventional...so my question is how do people who know what they're doing record seperate tracks simultaneously?

They use a multi-channel sound interface - such things do exist, you know! The interface on my laptop will record 16 separate channels simultaneously easily, (20 at a push), and you can monitor whatever you want. Not only that, but you can use it for separate submixes as well, whilst you are doing this, and have 4 different mixes appearing on 4 pairs of output sockets - all the time continuing to record each track separately. And all through one Firewire connection...