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DDR II v.s. QDR

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Dual channel DDR vs Quad channel DDR

The universal quote is correct: "More is better."

But it might be a while before you see either in mainstream PCs, all I know is that I think Dual and Quad exists in some server mobos.

Edit: Correct me if I am wrong about what you're asking about.
 
Ok just wondering. I thought for a minute that QDR was 2 times as fast as DDR. I didn't know it would be 4 times.
 
rambus is QDR. 4 bits of data are pumped through the bus every clock cycle. but QDR has much higher latency than DDR, so i think DDR II will work out much better, and dual channel DDR II will be the fastest memory available in the future. of course Hammer will chnge this, because u can have 2 opterons which are dual channel and each have 2 channels to pump the data through, and than the other opteron in the duallie can also have its own 2 channels, resulting in amazing bandwidth.

lets say u have ddr400 (3200 mb/sec) than dual channel it (3200x2=6400mb/sec). than double that again with the second CPU and u get 12,800mb/sec of theoretical bandwith, rivaling Video ram running at ultra high bus speeds. and all of this running DDR latency's of 1 or 2 clock cycles with a 4 or 5ns acess time, where RAMBUS has 32-50ns acess time and even higher clock cycle latencies.

so DDRII+Hammer=teh winnar!
 
CreePinG_DeatH said:
Ok just wondering. I thought for a minute that QDR was 2 times as fast as DDR. I didn't know it would be 4 times.

theoretically, it is 2 times as fast. DDR sends 2 bits of data per clock, as opposed to QDR's 4. but DDR can get those 2 bits of data acessed and sent out faster than RAMBUS ram can, so its a tradeoff.
higher bandwidth ceiling -vs- shorter acess time
 
From the information I have looked at on DDR-II it has nothing to do with a dual channel chipset.
It's a redesign of the gerber board to allow ddr to use chips and give the signal quality needed to go beyond the current 400(3200) limits.

DDR-II will operate at a lower voltage (1.8v) and use a different physical slot key design so it won't work in current ddr motherboards.

Dual channel ddr motherboards for current ddr will be out long before ddr-II is available retail.
 
Penguin4x4 said:
Why don't they put VGA Card memory chips in a system memory stick?

They can't with the current gerber board design they don't allow the signal quality needed to transfer data at that high of a rate without error.

Ddr-II will make this situation much better and the first ddr-II will be rated 400 and 533.

You will also be able to use them with a dual channel chipset and that should give enough bandwith to keep cpu's happy for awhile.
 
Yes, it actually can do a little more but the memory mfg's and jedec felt that changing to a new design with lower voltage would be better at this point.
 
Penguin4x4 said:
Guess my new rig plans will be put aside for a few more months, what with this new DDR-II, ClawHammer, and PC1333 RDRAM stuff coming. Oh, well.

just buy now, if not you will wait forever....

when DDRII is finally here at 400mhz than the 533 will be "just around the corner"

next thing u know quantum computing will be just around the corner


and DDR II has nothing to do w/ dual channel. i did not mean for it to appear that way in my post, dual channel is just another way of increasing bandwidth
 
I thought that QDR was similar to DDR, just with twice as much info being xferred.

I haven't really looked into it in detail, but I had understood that QDR was going to be low latency as well, just like DDR.
 
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