the following is my reply to a post and also pretty much my look into the RDRAM issue. i want to see more opinions. so i repost it here. all comments are welcome.
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1."The problem is, DDR SDRAM, while cheaper, does not have the bandwidth of RDRAM"
no. actually, as far as data throughput (i think this is what you meant as "bandwidth") is concerned, DDR is just a little bit behind RDRAM.
PC800 RDRAM has a data throughput of 1.6Gbytes/s. a dual-channel PC800 RDRAM config, 3.2Gbytes/s.
PC600 RDRAM, 1.2Gbytes/s. a dual-channel config, 2.4Gbytes/s.
PC2100 DDR, 2.1Gbytes/s, just about a bit lower than a dual-channel PC600 RDRAM config while way above the single-channel PC800 RDRAM config.
just think of "dual channel PC2100 DDR" that is probably on the way: 4.8Gbytes/s! amazing!! plus the latency factor, such a config will leave DC PC800 RDRAM config way in the dust!!
2."and P4 appears to be EXTREMELY bandwidth-dependant."
this is a bitter-sweet truth, while there is more bitter than sweet.
3."It is unknown, however, what effect will DDR SDRAM's lower latency will have on P4 performance."
generally speaking, latency is more important.
more to say: P4 is actually designed to live with RDRAM --actually, only Dual-Channel PC800 RDRAM. think about the "Quad-Pumped" FSB. its data throughput is also 3.2Gbytes/s, exactly the same as the throughput of a Dual-Channel PC800 RDRAM config. without this match (balance), other configs will simply kick the crap off into severe "data anaemia".
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Some are ignorantly happy,
While some, happily ignorant.
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1."The problem is, DDR SDRAM, while cheaper, does not have the bandwidth of RDRAM"
no. actually, as far as data throughput (i think this is what you meant as "bandwidth") is concerned, DDR is just a little bit behind RDRAM.
PC800 RDRAM has a data throughput of 1.6Gbytes/s. a dual-channel PC800 RDRAM config, 3.2Gbytes/s.
PC600 RDRAM, 1.2Gbytes/s. a dual-channel config, 2.4Gbytes/s.
PC2100 DDR, 2.1Gbytes/s, just about a bit lower than a dual-channel PC600 RDRAM config while way above the single-channel PC800 RDRAM config.
just think of "dual channel PC2100 DDR" that is probably on the way: 4.8Gbytes/s! amazing!! plus the latency factor, such a config will leave DC PC800 RDRAM config way in the dust!!
2."and P4 appears to be EXTREMELY bandwidth-dependant."
this is a bitter-sweet truth, while there is more bitter than sweet.
3."It is unknown, however, what effect will DDR SDRAM's lower latency will have on P4 performance."
generally speaking, latency is more important.
more to say: P4 is actually designed to live with RDRAM --actually, only Dual-Channel PC800 RDRAM. think about the "Quad-Pumped" FSB. its data throughput is also 3.2Gbytes/s, exactly the same as the throughput of a Dual-Channel PC800 RDRAM config. without this match (balance), other configs will simply kick the crap off into severe "data anaemia".
--------------------------------
-----------------------------
Some are ignorantly happy,
While some, happily ignorant.
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