From: "Dan Kucherich" :Sent: Saturday, May 26, 2001 11:47 PM
Subject: [PCBUILD] CPU's


Hi,

Can you put higher clock speed cpu's in mobos that support up to a certain speed and have the processor work at the highest supported speed?

For example, if your motherboard only accepts up to a 550mhz slot1 processor, can you put an 800mhz slot1 processor in it and it will run at 550mhz as long as you set the jumpers properly?

Thanks

Dan Kucherich

         
Dan,

Since the PIII processors are clock locked you would not have to worry about whether your motherboard supports the proper clock but you will have to find out whether your motherboard supports the proper voltage.  Not all processors support the same specifications.  You will also need to know the voltage needed by the processor.  If your motherboard supports the bus speed and voltage requirements you should be able to use the 800 Mhz processor at 800 Mhz.  Below are some of the differences between 550 Mhz processors and 800 Mhz processors.
 
The PIII 550 has a 100 Mhz bus and a Vcc Core Voltage of  2.00 V.  The PIII 550E with a cA2 stepping has a 100 Mhz bus but has a Vcc Core Voltage of 1.60 V, and the PIII 550E with a cB0 stepping has a 100 Mhz bus and a Vcc Core Voltage of 1.65 V.  
The PIII 800 with a cC0 stepping has a 100 Mhz bus and a Vcc Core Voltage of 1.70 V, while the PIII 800 with a stepping of cB0 has a 100 Mhz bus with a Vcc Core Voltage of 1.65 V.  The PIII 800EB has 133 Mhz bus with the cC0 stepping with a Vcc Core Voltage of 1.70 V, while the cB0 stepping has a Vcc Core Voltage of 1.65 V.

The 800 Mhz Celeron processor also implements independent Vtt and Vcc core power planes which must be supported by the motherboard.

If your motherboard does not support the proper voltage for the processor that you purchase the processor could be supplied to much voltage which would fry it.  Check the BIOS upgrades for your motherboard as often they will add more voltage settings, etc.  to support higher Mhz processors then the manual states.  

Mary Wolden

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