200 / 266 FSB, wth?

I notice two different FSB speeds when I search the web for Tbird processors, 200 and 266. What's the deal? Why aren't they all 266? you can use 266 with any type of memory, right? My god I can be an idiot!

-- *Ding Ding* Knowledge for the clueless!!! --

The only difference between a 200Mhz FSB Thunderbird and one for 266 is the multiplier, which is locked in the CPU. Otherwise, the CPU's are identical.

The following chipsets all support 266Mhz FSB, as well as 200.

VIA KT133A - Supports PC100 and PC133 SDRAM. Does not support PC1600/2100 DDR SDRAM

ALi MaGiK1 - Supports PC100 and PC133 SDRAM as well as PC1600 and PC2100 DDR SDRAM.

AMD760 - Supports PC1600 and PC2100 DDR SDRAM. Does not support standard PC100/133 SDRAM.

newer tbirds have fsb of 133 (thats 266 when you use ddr), and they are called Athlon-Cs 1GHz ~ 1.33 GHz.
they arent backward compatible, they wil run with 100 MHz fsb on older motherboards and run at whatever their multiplier by 100 MHz - thats 33% lesser than what they are supposed to - until you overclock them.

btw sdram and ddr have different memory slots - and currently only ALi's ALiMagik1 supports both of them at once, see Asus A7A266.

<font color=blue>die-hard fans don't have heat-sinks!</font color=blue>

So if I'm planning to use pc-133 or pc-150 memory does it even matter if I get a 200 or 266 processor? The 200 fsb units are $50 less than the 266!

-- *Ding Ding* Knowledge for the clueless!!! --