It works just fine for me without doing anything special. I have a laptop PC and a dektop PC, both with onboard Realtek High Definition Audio.
My laptop is connected to a cheap old Hercules XPS 510 speaker system, which is nearly antique but still more than good enough for me. It's 5.1 surround (6 channels) and has analog inputs (3 stereo mini-jacks) which are plugged into the blue, green and pink ports at the front side of my laptop. The green one can also be used as a mini-optical digital output port if necessary, but I don't have any digital speaker system or amplifier so that means I have to use the green one for both the front left and the front right channel. The blue one and the pink one are auto-sense, in other words: as soon as I plug a cable, the Realtek Sound Manager politely asks me what I want connected to the other end of the cable (Windows XP used to turn that polite question into a rude pop-up, but Windows 7 seems to keep it nice and polite now). So I took the blue one for both the rear left and rear right, and the pink one for both the center and subwoofer.
I set speaker config to 5.1 speakers and I checked the checkboxes for the speakers that I have. I unchecked low frequency management, because my speaker system is full range: its satellite speakers are not, but that doesn't matter because its built-in amplifier had its own low freq crossover circuitry already inside it when it came from the Hercules factory.
I check speaker fill when I listen to stereo music, and I uncheck it when I listen to 5.1 surround sound (if you hover your mouse arrow over speaker fill for a moment, you should see a small rectangle that explains what speaker fill is.......).
In the Standard Format tab, I select 24 bits 192000 Hz Studio Quality. That's it! Studio Quality is pumping into my room. You can verify that it works, by clicking the big play button that's in the speaker config tab, right next to the speaker config that you've selected.
On my desktop PC with Asus P5LD2 mainboard, it works exactly the same with only some exceptions: the green port is also auto-sense and so it can't be used for mini-optical digital output, but there's a separate (full-size) optical output anyhow, and an orange, a black and a grey port as well. So as a matter of fact, before I got my laptop, I was getting 7.1 surround with my 5.1 surround speaker system because I had added my old Panasonic portable radio cassette player to one of the extra ports, which worked brilliantly.
To be honest, the only thing that's actually bothering me righ now is that Windows 7 audio capability is still not allowing me to use my laptop's HDMI audio output to enhance the Realtek's and vice versa. I should be able to use my HDTV's built-in SRS TruSurround XT speaker system in juction with the Realtek's digital output, to get 9.1 surround sound. I've tried with ASIO4ALL and Virtual Audio Cable, so far without any luck.......
:devil:!
