Socket M2?

dorion

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Nov 10, 2005
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How is Socket M2 going to support DDR2 with only 940 pins? Won't it need to be 1050+. Am I just confused, I'm pretty sure from my reading that DDR2 has 56 more pins than DDR, and since M2 will be dual channel that means you need at least 112 more pins.

Can someone put my throughts in order?
 

dorion

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Ok let me retry to explain myself. Socket 754 allowed for single channel DDR. Socket 939 allowed for dual channel. Same as Socket 940.

754 + 184(another ddr channel) + 1(power?) = 939 pins.

Since 64s uses an integrated memory controller, which is why I think my little math up there stands true, when you upgrade to a different pin count of memory you need to change the amount of connections to the memory controller.

So DDR2 has 240 pins, thats 52 more than DDR. So at minimum M2 should have 1052, instead of the 940(that many sources confirm which is why I'm confused.)

So maybe this time you can answer my question without trying to insult me.
 

endyen

Splendid
Your question would make a lot of sense, if DDR@ support were a simple addon to A64.
With a re-design, amd can reroute ground, and to a certain exrent power.
M2 pin config suggests a rather major pin config redraw. It would be nice if there were more advancements, but unfortunately, Amd is not under a lot of preasure to enhance A64.
 

pat

Expert
I'd like to have a life with no concern but how AMD will make DDR2 working on their newer un released M2 socket CPU...

Seriously... you were really caring about that???
 

dorion

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My part time job involves making people sign a peice of paper for 3 hours. I can get very bored and must interest myself into a subject.
 

SidVicious

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You need to understand that many pins on a CPU are not connected to the core or unused and refered to as NC (No Connection) pins, likewise, some Vss and Vdd (respectively Positive Voltage and Ground) pins can be reassigned to data transfer by slightly modifying the core.

Same goes for the memory, not all pins are involved in data transfer, you don't need to connect the memory Vss, Vdd and NC pins to the ODMC (On Die Memory Controler), that's also why DDR2 SODIMM modules only have 200 pins instead of the 240 we see in DDR2 DIMMs.

Look at Chapter 5 of This AMD White Paper for a pinout chart of Socket 940 and Here for a DDR2 DIMM pinout chart.