airport express questions


The airport express is equipped with a mini-jack that is a combo: analog and digital toslink. Monster sells a variety pack of cables to go with the unit, including a mini-to-full toslink cable, and a mini-to-RCA cable.
How can I be sure that I am streaming digital audio with airtunes? Is there a box in some dialogue window that I need to check? For analog audio, which I don't want, does the airport express have a crappy internal DAC, or would the laptop be wirelessly streaming analog from its own crappy internal DAC? Laptop is a 5 year old Sony Vaio, windows XP. Thanks.
realremo
the computer can do this and much more if you have a decent machine. when you stream your music, how much cpu are you using? are you telling me that you are maxing out your cpu? the computer has to do quite a bit of work to get data off the disk, into it's memory buffers, and then package it up to send it over the network. all of this messaging of data happens in memory, after it is read from disk. if you system is using less than 80% of your cpu, it is not a big deal. now if you are saturating the cpu, now you need to offload some processing.

I don't believe streaming music, either from the native hard drive, nor from an optical drive, is very CPU nor memory intensive. My tower is a dual 2.7ghz processor. I can monitor CPU usage in real time on the Activity Monitor utility. Streaming files from itunes runs average around 4-6% capacity of the CPU with a few spikes now and then to 13% which are very brief. It take 87mb of real memory and around 1gb of virtual memory to stream music as well. Not even close to the machines capacities on any of those demands. I have three Squeezebox devices around the house and can stream music to all three, different tunes to each one, without a hiccup and still check email and surf the Internet. This is on a Mac. The Squeezebox interface does use the iTunes library, but NOT iTunes. It uses a web browser and indicates even less usage of the computers resources than iTunes demands. It is not a demanding task for a computer as far as I can tell. I'm comparing it to something like Photoshop, video or gaming software that is very graphics intensive. Someone correct me if I'm wrong.
jax2 - you are correct. that was point in my thread above. unless your computer is saturating the cpu, then it will have the capability to do a few more instructions to stream audio. i have 3 separate zones off my mac and it is barely doing any cpu or IO. what you will see normally is higher IO and not CPU. but again, nothing that a newer computer can't handle.
Just supporting/echoing your post, Rbsthno...sorry I didn't make that clear.
Realremo: Lifatec offers Toslink cables with the mini on one end and the full size on the other. I have used one from a Mac to the main system with good results (via iTunes). You can also get an adapter for almost pennies to go over the full size end and thus conform to your needs on the computer end.
Thanks Puerto, I have seen a link to their site in another thread, they are the ones who convinced me that maybe a plastic Toslink cable is OK. I am really interested in a mini/full toslink cable, just more of a pure thing than using the adapter, and will definitely check them out when I invest in PC audio.