Question about CPU External Frequency..

I just installed a new heatsink, and I'm ready to overclock. I went into the BIOS, Advanced Chipset Features. I understand most of the settings, but the one I don't get is CPU External Frequency. The manual says that the FSB is 2 times the value of this setting. I have an Athlon 2500+ and A7N8X Deluxe, but the value for CPU External Frequency in the BIOS is set at 100MHz. So does this mean that my FSB is 400MHz stock? I thougt that it was 333MHz. Also, if I set the Memory Frequency setting at 100%, is that 100% of 2x the CPU External Frequency, or 100% of the actual value it displays in the BIOS. Thanks.

Edit: I've also read about locking the PCI bus frequency, but I don't see anything in the BIOS that looks like it would let me do that. Is there something that allows it to be locked, or does this board not have a feature like that?

What memory are you using? Your Frequency setting should be at least 166. This then doulbles your ram speed. Your Multiplier of 10.0 or higher times FSB spped equals your total CPU clock speed.

You can set your AGP voltage to manual & don't change the settingof 1.5v & lock the AGP Frequecy into 66/67.

Hope this helps!

Pat

I believe the 'default' setting is for the PCI / AGP buses to be 'locked', i.e. they are set independently of the FSB, not a set ratio that scales up in proportion as the FSB is increased. Regarding the 'external frequency', that's just the 'real' underlying FSB speed. The default is probably the lowest setting, which is 100 ( aka 200MHz, since it's 'DDR'- i.e. two signals per clock cycle). A so called 333MHz FSB processor is actually running at an underlying clock speed of 166MHz, which is what you want your FSB set at. Memory works pretty much the same way, underlying clock speed of PC2700 is 166MHz, aka 333MHz because of the 'double data rate'. If you've got PC2700 and a 333MHz FSB processor, then you want the settings to be 166MHz and 100% (i.e. synchronous memory operation).