Hi sylvester80; Re: "But CL2 are the fastest parts on DDR200. Or did you mean to say CL3? You probably were referring to DDR266 cause you only mentioned DDR200."
I meant to say CL2, just as I did. PC100 (as defined by the Intel spec) is only available as CL2. PC133, on the other hand, is available as both CL2 and CL3. (This is a bit of a simplification, but is good enough for mom and pop.)
You wrote: "But CL2 are the fastest parts on DDR200." Actually, CL2 is the only DDR200 made. DDR266 is made with CL2 and CL2.5, rather than the CL2 and CL3 that I remembered. This means that DDR266 is never as slow in latency as DDR200. For the benefit of moms and pop, lets work out the latencies for the three types of DDR and the three types of PC1xx:
DDR266 CL2: 2.0 x 2/266 = 15.0ns
PC133 CL2 2.0 x 1/133 = 15.0ns (Benchmarked SDRAM system)
DDR266 CL2.5 2.5 x 2/266 = 18.8ns
DDR200 CL2: 2.0 x 2/200 = 20.0ns (Benchmarked DDR system)
PC133 CL3 3.0 x 1/133 = 20.0ns
PC100 CL2 2.0 x 1/100 = 20.0ns
Lowest latency is tied between DDR266 CL2 and PC133 CL2. Next fastest is DDR266 CL2.5, while slowest are PC133 CL3, PC100 CL2, and DDR200 CL2.
As far as bandwidth goes, the above six memory types rank as follows:
DDR266 CL2: 8 x 266 = 2.1GB/sec
PC133 CL2 8 x 133 = 1.1GB/sec
DDR266 CL2.5 8 x 266 = 2.1GB/sec
DDR200 CL2: 8 x 200 = 1.6GB/sec
PC133 CL3 8 x 133 = 1.1GB/sec
PC100 CL2 8 x 100 = 0.8GB/sec
Pretty clear that the DDR266 CL2 is going to perform considerably better than the DDR200. Big servers, which apparently care more about memory size than latency, are planning on using DDR200, while workstations and the like are concentrating on DDR266.
For the above numbers click on modules (or components) here, and download the .pdf data sheets:
micronsemi.com
Intel is (so far) only using DDR in their servers. So they are naturally using DDR200, rather than DDR266. Their choice is not an implication that DDR266 won't work, but is due to their market. Also, I agree with Scumbria, that it is highly likely (I would say a certainty) that the DDR systems Intel is working on for servers are dual channel. Because they have dual channel, DDR266 would provide more bandwidth than is reasonably needed.
It's kind of pointless to argue with you about the stability of DDR266. You're a thread moron, and no one could convince you of anything. But if DDR266 is so unstable, why would these passages be in a review of a motherboard containing DDR266:
While we did not have any problems with the DDR SDRAM memory system, the beta northbridge drivers didn't seem to work very well with the Detonator 3 drivers from NVIDIA. [I.e. typical early preproduction problems, but not with the memory subsystem.]
...
The purpose of the Samurai was to show the world how to build a northbridge that can work reliably with the DDR SDRAM, not to build the best chipset or AGP4x implementation on the market. [Which is why Micron cancelled it when VIA came through.]
...
I almost fell out of my chair! The DDR system slaps the competition silly!
aceshardware.com
Since Micron cancelled the Samurai, we can only assume that the alternative DDR systems provide better performance than it did.
-- Carl |
