I am considering the purchase of a Lenovo ThinkStation desktop computer.  It has to work with Sonar, a USB MIDI interface, a USB audio interface and a 5.1 speaker system.  Lenovo computers are not geared toward music applications but have plenty of speed, memory, etc.  The ThinkStation system specs say they work with 5.1 HD sound through a Realtek ALC662 codec.  However, they have a single 1/8" mini-plug line output, whereas 5.1 speakers utilize three 2-channel outputs (front L & R, rear L&R, center & woofer).  Here are my questions:
 
1.) Would a computer of this type be a wise choice for music applications?
2.) Is there some way that 5.1 HD works with only one line output?
3.) If the answer to #2 is NO, then what type of sound card would be necessary to achieve what I'm looking for?
 
I ask #3 because I was under the impression that my USB audio interface -- a FocusRite Scarlett 6i6 -- IS my sound card for all intents and purposes but it does not have 6-channel output; it has two sets of stereo and the unit does not decode stereo to 5.1.
 
Thank you for any advice you can give on this.
UCG Musician

I can't discuss Thinkstation performance (professional liability issue), however if you're using a USB audio interface, I wouldn't worry about the Realtek and 1/8" output.  You'll only be using the PC for processing and the USB connections.
Does the USB Audio Interface support 5.1 output?

No, the 6i6 only has 4 monitor outputs, essentially left and right channels going to two sets of stereo speakers.  As I understand it, 5.1 surround sound is simulated by sound cards or software.  The 6i6 has neither the required number of outputs nor a 5.1 simulation feature.

Maybe this can help
 
https://fredpearson.wordpress.com/2013/07/01/audio-interfaces-suitable-for-5-1-surround-sound-monitoring/
 
 
or this
http://www.musiciansfriend.com/pro-audio/m-audio-revolution-5.1-surround-sound-card
 

Lenevo should be fine for most work, depending upon the cpu etc.  The faster the chip, the more memory and dual disk drives will make your music life so much better.  The Focusrite is good, too, from what others say here.  When you get the exact specs fly them by in the computer forum and they will let you know.
 
@

This topic comes up from time to time. 
People wanting surround sound for gaming and then use the same computer for a DAW. 
 
It's simple. Use your on board audio for gaming and your audio interface for your DAW. 
 
The other situation is people wishing to mix for video and requiring professional surround monitoring. That will require a audio interface with 6 or more outputs. 
The 6i6 actually does have that. You'll need monitors that take SPDIF to utilize the 5/6 channels of the 6i6. You then use mix control and the DAW 1- through DAW 6 sends from Sonar. 
 
And Lenovo makes good stuff, but be aware they are of 2 catagories. The commercial models used world wide by millions of offices, hospitals etc and then the consumer models. The commercial models are bullet proof.. The consumer stuff ,, same as Acer or HP really. 
Building your own, if your up to it, is best bang for the buck,, or for a small fee there are people here who build DAW's and you wil get top notch service from them from what people say.