Confusion about RAM/FSB/Multiplier relationships on Core 2

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I'm considering switching to a core 2 due cpu after years of just AMD
machines (only upto S939 DDR and not DDR2 machines).
However coming from such a background I'm finding I'm getting confused
about the multipliers/FSB etc. and it seems a number of sites seem to
use get confused themselves talking about whether they they mean RAM or FSB.

Let me explain what I think I know:-

1) At stock speed, As far as I know a E4300 runs at 1.8Ghz with a 9x

2) The CPU speed is always FSB x multiplier and */_not_/* RAM speed x
multiplier? (some articles seem to imply its RAM x multipler)

3) At stock speed, its running on a 200Mhz FSB with the RAM at 400Mhz?  
So the RAM in this case always runs 2x the FSB?

So assuming I wanted and could reach 3Ghz with this E4300, using 800Mhz
RAM I could do this by :-

Setting the FSB to 333, that means the RAM runs at 666, the CPU runs at
333x9 giving approx 3Ghz?

Any helps or links to guides to RAM/FSB/Multiplier relationships on Core
2 CPUs greatly appreciated.

Re: Confusion about RAM/FSB/Multiplier relationships on Core 2

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FSB x Multiplier=CPU speed...

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With DDR/DDR2 yes.

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Yep.....that's it.

Your FSB determines the processor speed. You just need to keep your memory
within it's operating range which could vary depending on the rated speed,
latency and several other things. 800mhz rated speed would probably be able
to go a bit higher (most modules will). The best way to get your maximum CPU
speed is first to find how far you can go with the memory divider well below
or at your memory specs. Once you find your best CPU speed that is
completely stable you can then raise your memory divider and find where your
memory begins to give you errors, then back it down a bit and leave it
there. A very slight increase in your memory voltage is ok but I try and
keep it at default or as close as possible. You also may need a slight
increase in your CPU core voltage to get to 3ghz with that processor,
although there are folks that get there at stock voltages in a few cases.
When I say slight increases, I mean no more than a 10% increase at the most
with the CPU core voltage and maybe not even that much with the memory. You
can kill the memory and CPU with overvoltage. If an Intel CPU gets too hot
it will shut down with no problems, but overvoltage can kill it. Do
everything in very small increments. Good luck.


Re: Confusion about RAM/FSB/Multiplier relationships on Core 2

Ed Medlin kirjoitti:

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This is the basic idea.

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No. Not always. There could be some settings in more advanced
motherboards enabling other proportions. Using these settigs it would be
possible, for example, to run your cpu with a FSB of 250MHz still being
able to run your memory @FSB of 200MHz, thus making it possible to run
your DDR400 at its stock speed.

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Yes, if the multiplier of the CPU is 9. You could check if the
motherboard allows you to run the memory at some different proportion
than 1:1 to make it possible to use say your 400MHz memory. If that's
what you have in the top drawer, of course :-)


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