Answer to PCI Lock Question on nForce2 Boards

[BeaverTooth]

I found this in the Lost Circuits review of the Asus A7N8X.

quote

The A7N8X offers bus frequencies up to 211 MHz. Keep in mind that the MCP-T is linked to the SPP via HyperTransport and runs at a fixed frequency. Therefore, unlike in conventional designs, there are no worries to run the PCI bus out of spec.


Thats why there is only an AGP lock, because the PCI runs seperate and is fixed at its frequency due to the HyperTransport. Overclocking here we come!

 

[Insane3D]

Very interesting find. The theory I had was that the PCI bus might be derived from the AGP bus directly, so that when the AGP was locked @ 66mhz, the PCI was locked @ 33mhz. I will be hopefully running 200mhz FSB on my new 8RDA+, so I will be able to see firsthand any bus issues.

 

[Peter]

It all depends on what combinations the clock synthesizer chip on the mainboard can produce. A chipset that supports asynchronous (or call them "locked" if you please) bus speeds doesn't help much when the board's clock PLL doesn't produce that.