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Complete NEWB. I need to know about DDR Ram.

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jarablue

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Joined
Mar 3, 2002
Location
Worcester, MA
Hi I am new to this forum so go genle on me. I don't under stand the speed of DDR ram. If it is 2100 does that mean it is 133 mhz = 266 mhz? I am also kinda confused about how I have to change the bus speed on my p4b266 c. What is this 4:3 ratio? If you guys can explain it to me I would appreciate it. Thank you.
 
DDR

Welcome to the forums!

Double Data Rate SDRAM. PC2100 is rated for FSB of 133, PC2400 is rated for FSB of 150, PC2700 is rated for FSB of 166. Multiply by 2 to get the effective performance of DDR. 133=266, 150=300, 166=333.

The 4:3 thing is probably the PCI divider. The PCI bus runs at 1/4 the FSB, when the FSB is at 133+. So at 133, everything on the PCI bus is running at 33Mhz. At 100 FSb, it'd use the 1/3 divider. So at 100, it'd still be running at 33Mhz. By overclocking the FSB, the PCI bus and everything on it runs faster than its specifications. So, at 150 FSB on a 1/4 divider, everything on the PCI bus would be at 37.5 Mhz. Very often, PCI cards or HDD's will have problems running too far out of spec.

FSB adjustment should be somewhere in your bios if your motherboard supports such adjustments. It might be labeled "system bus" or "front side bus".

Ask about it in the Motherboards section and you should get answers from people who have or have used the same motherboard.
 
jarablue said:
Hi I am new to this forum so go genle on me. I don't under stand the speed of DDR ram. If it is 2100 does that mean it is 133 mhz = 266 mhz? I am also kinda confused about how I have to change the bus speed on my p4b266 c. What is this 4:3 ratio? If you guys can explain it to me I would appreciate it. Thank you.

2100=2.1GB/s:133 Mhz. 2400=2.4 GB/s:150 MHz (unofficial spec). 2700=2.7 GB/s:166 Mhz

You change your bus speed from the BIOS. It's there in CPU speed selection.

If 4:3 is in the mem section, it basically means to run you your mem asychronously, or at 133 MHZ with your CPU at 100.

Sang
 
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