3.
You're quite right in your measurements, but there's one thing that doesn't seem to be clear.
DDR3 is going to be slower than DDR2 at the same, or even similar speed. That's an obvious consequence of the design. The entire point of DDR3 is that it can run at twice the speed of DDR2. By which point it has made up the deficit!
DDR3-1600 is actually a fully-specified, JEDEC operating speed. Just like DDR2-800, DDR-400 and PC-200 SDRAM. It's not pushing the specification at all.
All of these operate the internal RAM array at 200 MHz, giving them exactly the same fundamental latency.
Now, you can go faster As you've observed, for suitably nosebleed prices, you can get DDR2 that runs 50% faster than JEDEC dreamed. Just like you can get DDR1 that runs 25% faster (DDR-500).
It's not (yet) clear that we won't see DDR3-2400 as DDR3 matures. I'm kind of scared of signal integrity at that kind of speed, but the basic RAM demonstrably exists.
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Posted by: EEboy

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Date: 08/24/07 01:45:54 PM]