CPU FSB frequency and RAM frequency agreement, and BIOS CPU support.

By Rabbit
Jan 17, 2005
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  1. I was at Goodwill yesterday and I found an ECS K7SEM v1.0 motherboard for $6. Assuming that it works, I wouldn't mind getting an AMD cpu and some RAM to get this going as a multi-purpose additional computer for my apartment.

    The original intent of this board was for AMD processor running at either 100Mhz or 133Mhz FSB. The manual for the motherboard says that the RAM speed cannot be less than the processor FSB. For example: according to the manual, if the CPU has a FSB of 133Mhz, then PC133 RAM must be used and PC100 RAM cannot be used. If a CPU has a FSB of 100Mhz, then either PC100 or PC133 RAM can be used, but not PC66.

    This manual was printed in 2001. However, in 2002/2003, a new BIOS upgrade was created for this board to allow support for Athalon XP 2100 and 2200 processors.

    I was looking at an AMD XP processor at newegg and realized that the FSB is 266Mhz, according to the specs. I always get confused about FSB ratings. Are you supposed to divide this number by 2 with AMD chips? Like if the FSB is 266Mhz, should I use PC133 RAM to be compliant with the statement in the manual about using RAM that matches or exceeds the CPU FSB?

    Another question I had is related to the new BIOS update that supports the newer processors. Would I need to use an old processor in order to update the BIOS before I can use the XP processor? Or will I be able to update to the XP supporting BIOS with the XP processor already in the socket?

    If everything goes smoothly and I have some compatible old RAM laying around, I might be able to build this entire system for under $100! I am a little worried though about why this motherboard was at Goodwill, and what might have happened to it before and after it got there. Without having turned it on, it at least looks like it's in great condition. Some of the jumper settings are wrong, but that can easily be fixed. If this works, it might be the 2nd coolest thing I've ever gotten at Goodwill, falling just shy of Herb Alpert's Whipped Cream LP. ;)
  2. Didou

    Didou Bowtie extraordinair! Posts: 5,899

    When an AthlonXP is advertised with a 266mhz FSB, it is actually running at 133mhz but its DDR nature makes it run as fast as a 266mhz FSB. Any 266mhz AthlonXP should work on that board provided it isn't above the 2200+ ( 1800mhz ).
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