pci data question

[spudmatic]

i have a ht omega striker 7.1 sound card. my question goes like this.
im curious about the data transfer differences between onboard audio and a add in sound card.
what are the differences? correct me if im wrong please. onboard sound card uses cpu power to do whatever it does to give me sound thru my speakers. i can only assume that an add in sound card would use the pci bus lane to transfer data. which of the 2 will have a smaller affect on overall performance of the system.

for the sake of the matter, lets say onboard sound drops frame rate by 3 fps in whatever game im playing due to the fact that im using the cpu to do the work.
now lets say i use an add in card for sound. am i going to lose frames in whatever game i play due to the extra data moving along the pci lanes? do the video and sound use the same lanes? aside from sound quality, is there any other reason to use an add in sound card? is it worth it to use a sound card?

i wont say im a huge audiophile, but i do like my music nice and clear. my home theater is all polk audio, onkyo equipment in a 7.1 setup so i can tell the difference between good and bad sounding equipment. this is more about general performance of the system.

computer setup is a rampage 3 extreme, 930cpu. ram isnt bought yet but it will be a 16gb kit. and a temp gtx550. will get a couple new cards for sli when nvidia finally releases their new cards. asus vg236 120hz and a samsung 2233rz 120hz. will be using my logitec 5.1 speakers for sound. will be overclocking as much as i can. everything is watercooled.

a small explanation on the differences in data transfer would be fantastic.
thanks all

[Babrbarossa]

If anything the dedicated soundcard will give you better performance by offloading sound processing to the card- modern onboard sound uses sound chips, but the CPU still needs to do some work. Either way, pretty negligable. Just turn off the onboard sound in the bios to gain any advantage that the card might have- there is no PCI bottleneck to worry about.

[Dragonstongue]

Well in concept, it depends on what OS is being used, windows 7 and vista are both software driven audio cues, so even if you have onboard or a soundcard, it is by and large being driven first by windows then cpu to direct it sort of speak then finlly shifted to the hardware being the chips or soundcard. The difference is almost negligable in windows 7/vista because the HAL layer was removed, but this is also good, because you generally do not suffer performance penalties just overall sound quality instead.

Windows XP and prior and possibly other OS on the other hand, do treat audio directly where the cpu has to crunch it all, if there is proper sound hardware to deal with it, it will intercept the stream and handle it for much less performance hit then letting the cpu do it itself.

Now, like I said, I know windows 7 and soon to be 8 are all more or less software driven which feeds to whatever hardware you have, it is not the best thing really, as things did sound alot more "lively" before, but, you can still tell the difference of a good quality soundcard vs run of the mill onboard, not in a performance side, but most certainly in an audio quality side, sounds are just more pronounced, bass, sharp, however you want to look at it.