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Help!!! I don't understand Ram Dividers, and overclocking

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November 7, 2007 2:15:22 PM

Hey Everyone

Got a question that i just can't figure out.
I have been trying to wrap my mind around how ram effects overclocking and dividers.

I have an e6600 and want to overclock it as high as possible
so i bought 2gb of corsair Dominator ram @ 1066.
My question is what FSB speed should i be looking to hit?

I have read that with DDR2 800 FSB of 400 gives a 1to1 divider but i don't really understand that.
Does an incorrect divider cause more hard page faults because it looks like i am getting alot of those
but again i don't really know how many is alot.
If you could clear up my confusion of ram dividers and help with finding my optimal FSB speed
i would be very appreciative.

E6600 @3.15
Corsair Dominator 1066
8800 GTS 640
Asus P5wdg2 ws Pro
November 7, 2007 2:20:58 PM

all i know is that 1:1 means the RAM and CPU run at the same mhz. RAM is double the cpu FSb (eg. ddr2-800) but is infact 400mhz. So run the CPU at 400mhz and the RAM at ddr2-800 and its 1:1.

I would look for CPU 400 mhz at 1:1 or 1:3 (ddr2-1200) if your motherboard and ram can handle it.
November 7, 2007 2:40:33 PM

The Divider takes the FSB and runs the memory at a set "divider" of the Bus Speed.

As can example... if you have a bus speed of 266 and set the memory to a 1.5 divider you get 400 MHz memory. Memory is dual channel and so transfers data at two times the MHz. 400 = 800, 533 = 1066 and so on.

You set the divider to 1:1 when overclocking the CPU to find stability so the RAM isn't the issue (400 Bus Speed = 800 MHz memory which is at or below most specs.)

There is no "incorrect" divider, there are set options in the bios that will take the Bus speed and multiply it to give you a memory speed. Try to run the memory as close to specs as possible while overclocking the CPU until you get it stable.
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November 7, 2007 3:01:14 PM

Thanks Cnumartyr

Your post helped alot. It assumed that there was no incorrect divider but wasn't sure.

What is the point of underclocking your processor i.e. lowering the multiplier
and setting a higher front side bus speed? In what situations would someone want to do that?

Thanks
November 7, 2007 3:19:16 PM

In theory the faster your bus speed runs the quicker the processor will communicate with the rest of the computer.

You don't really "underclock" the processor but you do lower the multipler. As an example... Running 400 MHz Bus with an 8 times multiplier on the CPU will give you 3.2 GHz. If you were running a 320 MHz Bus with a 10 times multiplier the CPU is still the same speed inside (3.2 GHz) but the Bus is able to deliver information in and out of it faster.

That is the theory.. in the real world I think moving from 266 to 333 Bus on a Dual core gives you something like a 3% increase at the same CPU speed. It is more important for Intel Quad Cores. Because it is actually TWO dual cores right now making up a quad core the two sets of cores communicate with each other over the bus. Obviously this is MUCH slower as it is not running at processor speed. Going from 266 to 333 on an intel Quad has seen as much as a 10% increase.
December 3, 2007 9:32:18 AM

Wait a minute... Do you mean to say that 320MHz is faster than 400MHz?
Please clarify.
a b K Overclocking
December 3, 2007 1:34:40 PM

I'm sure CNU meant that the 400/8 combination enjoys faster data throughput due to the faster FSB. Even though a 10x/320 combination has the same clock speed as far as the processor.
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