Onboard sound and PCI bus speed

[tsowen]

I just realize that the ALC650 AC97 audio codec on the Abit IT7 MB only works when the PCI bus frequency is set to 33MHz. When the frequency is set to 37MHz or higher, the audio codec stops working. I am wondering if this is normal? I check the ALC650 spec. There is no mention about the PCI bus frequency. If I am using a PCI sound card, I will understand why it only works at 33MHz. But does the onboard audio codec have anything to do with the PCI bus frequency? Is the onbard audio codec considered a PCI device?

BTW, I couldn't find the spec for PCI on the Abit IT7 MB. If it supports PCI 2.1, shouldn't it support up to 66MHz?
Thanks.

Steve

 

[Peter]

66-MHz PCI is something entirely different. Yes it's in the PCI 2.1 specification, but it's not something you HAVE to have. Besides, 66-MHz PCI is limited to two slots - in order to build a useful board sporting it, you need a chipset that has two PCI busses, a fast one and a normal one. Expensiiiiive.

regards, Peter

 

[Blain]

How does the PCI lock operate on the IT7? Can you lock it at 33MHz. and run the FSB at whatever speed you choose, or is there a FSB limit while using the PCI locked @ 33MHz?

 

[tsowen]

PCI bus speed can be set to 1/3 or 1/4 external clock, or fixed at 44MHz, 37MHz and 33MHz. No limition on FSB speed.