Now this is something i have been wondering for a while, now when someone were to run onboard sound it uses the cpu in conjunction to help produce your sound correct?
But bottom line is, is it beeter to run a pci2.1 sound card or just use the onboard audio?

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There is no one size fits all. I am not a game player so I use intergated HD sound that sounds great and was totally free. If the use of the onboard was interfearing with game playing then one might consider using an add in card. If I felt a need for an add in card I would look for a PCIe based card, if they are available yet. I do think that for the most part what you have heard about sound cards is based on the experiences of the gaming community at large. There are two facets to this. One is the CPU cycles, which may lower the frame rates at which a game may play but I don't think in reality you need 100 FPS anyway. The second is probably more legitimate. That is, Creative labs sound cards are the defacto standard for the special effects that can be used when playing games. If you want or need those effects I don't think you have no choice but to use a Creative add in card.

One last point. All sound uses some CPU cycles. The pci bus is still dependent on the processor to some degree. It is a matter of what degree the processor is used. If you can perform whatever tasks you need to while using CPU cycles for sound, what harm is there in that. You just need lots of horsepower, which all modern processors now have.

While it's true that onboard sound does use some CPU cycles, the performance hit is very minimal, especially considering the speed of today's CPUs. Onboard sound has gotten quite good too so there's very little need to move to a dedicated soundcard, unless you're a true audiophile or need specific features not offered by the onboard.

Onboard sound chips usually are tied into a PCI channel, like using a PCI sound card, only it's soldered to the motherboard.

The quality all depends on the amount of detail put into the design of the motherboard. If it's designed well, there should be no or little static, feedback, and electronic noise. I have seen really crappy built in audio hardware.

Also who made the sound hardware? some knock off AC'97 no name compliant chipset, or someone decent? I tend to think CMI chipsets suck as an example.

Last is the drivers. Have heard echoing, skipping, slowdowns, and jidder all from crappy drivers.

In the end, if you want to be sure, you may want to go with a ceative labs sound card, or similar name brand known for audio quality.

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