What's the second number?

I've searched and cannot find an answer (I'm new by the way):

I have a several PCs with Asus motherboards. Under 'Advanced' in the BIOS I have an option for 'CPU External Frequency' which I understand is the frequency of the System Bus (Front Side Bus) and that this is effectively doubled in a DDR system.

The only problem is it's actually two numbers separated by a slash e.g. 133/33

What is the second number? Is it the PCI bus speed?

I have PC2100 RAM in one system (A7V8X) and I can up the 'CPU External Frequency' to 149/37 before the BIOS warns me about the memory speed. I understand that PC2100 is rated at 266MHz so I would guess the standard setting would be the 133/33.

Is 149/37 running the memory at 2*149=298MHz and is that too high? And is that second number, 37, going to cause problems e.g. with data integrity on the IDE channel (Maxtor HD)?

Ned said:

The only problem is it's actually two numbers separated by a slash e.g. 133/33

What is the second number? Is it the PCI bus speed?

I have PC2100 RAM in one system (A7V8X) and I can up the 'CPU External Frequency' to 149/37 before the BIOS warns me about the memory speed. I understand that PC2100 is rated at 266MHz so I would guess the standard setting would be the 133/33.

Is 149/37 running the memory at 2*149=298MHz and is that too high? And is that second number, 37, going to cause problems e.g. with data integrity on the IDE channel (Maxtor HD)?

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Welcome to the forum

Yep, looks like the munber is the PCI bus soeed.

Good points about the RAM. It might be a bit high for the RAM to run but you might get lucky. I would hesitate running the PCI higher than 36 Mhz maximum, try to keep it as close to 33 as possible. You could bork your hard disk at high PCI speeds....

37 is probably ok for the pci speed. Really it depends on your hardware more than anything though. Some hard drives are pretty forgiving. Some corrupt real easy. 38-39 is where I started running into issues.