The traditional advice is to disable on-board sound when installing a discrete sound card, but then again that's from the days of IDE drives. However, that advice is usually not followed when a discrete graphics card including sound is added. I sent a query to ASUS and their advice was to not disable on-board sound when using one of their graphics cards.
I have a DZ68BC with a Creative sound card, one of the best it ever produced. But Creative never released a Linux driver for it. Now that Microsoft is playing hardball with W-10 updates, I want to convert this PC into one that can run W-7 or a few flavors of Linux simply by switching SSD system drives in a dock. I've got the front jacks connected to the Creative card, so the only time the on-board Realtek output would be accessed is when I insert a plug into the motherboard connectors. I'll use the Creative card with W-7 and the on-board Realtek with Linux. Hence my question: would there be any problem in leaving the on-board Realtek running alongside the Creative card?