I am very new to recording but know about computers.  This might be a dumb question but here it goes.
I built a pc with WIndows 8.1 x64 to be used as the DAW.  The mother board is a Gigabyte GA-Z97X-UD7 TH motherborad that has a Realtek ALC1150 onborad soundcard.  I also purchased a Focusrite Scarlet 18i20 with a USB input.
 
So does the soundacard matter or does the 18i20 do all the work and the soundcard is not even used?  I may be totally missing the
point but that is the question.
If the soundcard does still matter, any suggestions on brands, pcie, usb, etc.
 
Thanks

The short answer is no, it does not.
 
You can not use more than one soundcard in DAW without troubles with synchronization.
You still can use internal card for windows sounds and even route it's output to Scarlet input (practical in case you do not have separate headphones/speakers).

Often people recommend to disable the internal sound card. I have not done that and maybe that is why my daw sometimes crashes or freezes.

You could probably disable the onboard soundcard in the BIOS if you like, or if you have it enabled route all the windows sounds through it away from the Scarlett  (Check "Sound" under control panel)... 
 
You will set up the Scarlett ASIO driver within Sonar, make sure you download the latest drivers from the Focusrite web page. I also suggest having the latest motherboard BIOS and chipset drivers installed.
 
Cheers...

Thanks...my question is answered.  So basically, Focusrite Scarlet is the soundcard.  The ASIO driver was my other question.  I have not installed Sonar x3 or the Focusrite yet but I will make sure I install the asio drivers and have them selected in Sonar.
 
Also, I have already disabled all windows sounds.  So if I disable the onboard soundcard and disable all windows sounds, would I need to always have the Scarlet on with headphones or monitor speakers attatched if I wanted some playback when not recording?.  Sounds like it from what azslow3 said but not sure.
 

I have a similar MOBO and set up. I just ignore the on board card , nothing is plugged into it and I did not have issues with it interfearing. Sometimes we will disable the on board card if it is causing issues with taking over Sonar. Focusrite drivers seem to not have this issue. 
 
Install and test the Focusrite drivers before you install or open Sonar. This way when you first open Sonar it will not even look at the realtech. I put Sonar in WDM and run the audio test thing before setting it to ASIO. 
 
Also if you have any older versions of Sonar install them first. I install barebones 8.5 to get True Pianos as example. Apparently it's not good to install older versions after the newer versions or important things get overwritten. 

Once in a while someone will have an issue when their on-board sound is enabled, but from my observations this is not a frequent situation.
 
I do not choose to disable my on-board sound, and instead sometimes assign it as my Windows Default Audio Device, while assigning the use of my dedicated audio interface to applications like Sonar.  Then, the two sets of audio usages do not conflict, and I could play YouTube at the same time I run Sonar, with no trouble.
 
If I AM running as above, I then have to have either a separate set of speakers for the PC speaker output, OR I split the output from the PC speaker jack and route left and right into 2 inputs of my audio interface.  Either way works, but if audio interface inputs are not available then indeed the separate speakers would be the method chosen.
 
On the other hand, I ALSO have multiple HDTV's that I use for Sonar display monitors, and these have their own built-in speakers, so my usual configuration is to set the Windows Default Audio Device to one of the 2 HDTV's.
 
So, if you are having conflicts with using your on-board audio, then you may want to disable it and use some other method, but if you are not, then I would recommend one of the above choices.
 
Good luck, 
 
Bob Bone
 

sounds good..it all makes sense.  thanks for the quick responses!

I leave the soundcard enabled so that all the windows warnings etc. at weird sample rates and bit depth are routed to it.  I hardly ever turn on the speakers tho (they are on a spare outlet not the recording ones).  My TC Konnekt interface is not very forgiving with those and will get "confused." Unlike the Reltek card which is made for such noises but not recording use.  That way works for me - your Scarlet might be different.
 
@

Hey Bob, after Craigs thread about Video card Hi Def Audio drivers causing huge DPCLAT issues one needs to approach using HDMI for audio with caution. I think it was just AMD and Nvidia anyhow. Can't find the thread.