That's why there are soundcards with external break out boxes. In my research, if the interal card is placed in the farthest slot from the videocard and processor, and an external breakout box is used for the input/output connections.. there shouldn't be a problem. And as far as I know, the problem with having the sound card close to the other components, such as the videocard, is that it creates slight bg static, lowering the s/n ratio. At least with my soundcard, I have noticed no issues with the s/n ratio at all, and even if I turn my stereo up to unlistenable levels, I don't hear any white noise or static at all, with nothing playing.
Now, I guess it depends on your computer system, and if you have to place the internal soundcard right beside the processor / video card. Anyways, it would still be better than an onboard soundcard that is part of the motherboard though, which is definately close to the other components.