Ok, so the 1Ghz FSB is unrealiztic
Your last post was a much better explaination. I hadn't thought of the system bus interface. However there are a few things that still didn't make sense to me. In your last post you said:
<i>let's look into the architecture of a PIIIeb for example. it features a 64bit system bus interface running at 133MHz, through which it talks to the northbridge. this is a built-in spec. this is the actually limit. it means you can not put the system bus under too much stress.</i>
If 133Mhz FSB on PIII chips is the limit, then why are so many overclocked past 150Mhz. Some are even clocked past 166Mhz. At this point the memory can't handle any more (It takes better that 6.0ns memory to run over 166Mhz).I don't think using the PIII as an example of the impossibility if FSB overclocking is valid. PIII's <b>can</b> considerably overclock their FSB. With Intel chips having locked multipliers, this is the only way to overclock them.
I realize the difficulties with overclocking the EV6 bus on the AMD chips because it is double pumped. I always thought system bus itself was the problem. Is it infact the system bus interface of the processor? Do the new 133MHZ FSB Athlons have a new stepping? I didn't think so, but they might. In an AnandTech article (<A HREF="http://www.anandtech.com/showdoc.html?i=1344&p=3" target="_new">http://www.anandtech.com/showdoc.html?i=1344&p=3</A>) about the AMD 760, Anand says this about the difference between the 100Mhz FSB and 133Mhz FSB Athlon chips:
<i>The <b>only</b> thing that sets the 1GHz and 1.2GHz CPUs apart from their 100MHz FSB counterparts is their clock multiplier. While the 100MHz FSB Athlon running at 1.2GHz has a 12.0x clock multiplier (12 x 100 = 1200MHz), the 133MHz FSB version only has a 9.0x multiplier (9 x 133 = 1200MHz). Obviously if you have a motherboard that can get around the clock multiplier lock this won’t pose a problem to you, but if not, then you will want to make sure that you only use a 133MHz FSB CPU on an AMD 760 board.</i>
This is what lead me to believe that one could use a 100Mhz chip at 133Mhz in an AMD 760 motherboard if it has an unlocked multiplier.