Via KT133A buss speed facts, please straighten me out here!

[Hulk]

I'm having a little debate with a friend.

He has a Duron 750, not overclocked with a Via KT133A chipset motherboard.

I know the buss is doublepumped at 200MHz.

What parts of the chipset are running at this speed?

What is his memory speed? Or, that is what speed is it being accessed? 100MHz or 133MHz?

If it is 133MHz, as he says, then there must be a memory:fsb multiplier of 4:3 in there somewhere, right?

???

Mark

 

[Green Man]

Yes, the KT133A allows allows the memory speed to be set to 133 when the FSB is 100.

 

[tcsenter]

<< What parts of the chipset are running at this speed? >>

First, there is generally a difference between clock frequency and bus frequency. 'Speed' is about the most generic term you can use, I try to stay away from it. It can mean a few different things.

When you refer to 'clock' speed or frequency, you're really referring to the frequency produced by the "clock" generator. When speaking in these terms, you're not concerned with whether the data rate is SDR or DDR, because it is irrelevant. Clock frequency always refers to the same frequency whether it is SDR or DDR.

When you refer to 'bus' speed or frequency, then it could mean either the clock frequency alone or the clock frequency x data rate.

The entire Duron/Athlon system bus runs on a spec clock frequency of 100MHz or 133MHz (except AT/ISA/PCI/AGP busses which are derivatives of this clock frequency). Certain parts of that system bus are single data rate, others are double data rate, but they're all running at the same clock "frequency" (100MHz or 133MHz).

On non-DDR Duron/Athlon chipsets such as the KT133A, the only part of the system bus using DDR is the FSB (Front Side Bus) between the chipset and the CPU. The memory bus is single data rate.

<< What is his memory speed? Or, that is what speed is it being accessed? 100MHz or 133MHz? >>

The KT133A has asynchronous bus ability, which is to say the CPU can use a frequency that is different from the memory. You can run the CPU at 100MHz and the memory at 133MHz (e.g. 100/133, 100/100, or 133/133).

If his memory bus is running at 133MHz, the FSB (CPU external frequency) could be either 100MHz or 133MHz.