DDR3 Ram timing

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thread starter Nv1d14 Jun 22 2010 + PM | QUOTE | PERMALINK | REPORT

How come the timings in DDR3 ram are so high? DDR2 has such lower timings.

yuyulian 06/22/10 + PM | QUOTE | PERMALINK | REPORT

cuz the higher speeds/frequencies make up for the higher latencies

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BrokenLime 06/22/10 + PM | QUOTE | PERMALINK | REPORT

Higher bandwidth requires higher latencies. DDR has lower timings than DDR2, which has lower timings than DDR3. That being said, there's a point when high frequencies do not give noticeable increases in performance.

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Nv1d14 06/22/10 + PM | QUOTE | PERMALINK | REPORT

@ Yuyulian. Thanks, but that doesnt answer my question. That doesnt say WHY higher speeds have higher latencies. @ BrokenLime. Ok, but why is that. Why does a higher bandwidth require more latency?

BobR 06/23/10 + PM | QUOTE | PERMALINK | REPORT

It's not that those two factors are locked together- It's that DDR3 has higher latency, just as a result of the way it works. To help get around the effect of that, manufacturers try to clock the RAM faster.

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Nv1d14 06/23/10 + PM | QUOTE | PERMALINK | REPORT

[quote] BobR : It's not that those two factors are locked together- It's that DDR3 has higher latency, just as a result of the way it works. To help get around the effect of that, manufacturers try to clock the RAM faster. [/quote] So the timings are higher just because they are? Theres no particular reason?

djpinc19 06/23/10 + PM | QUOTE | PERMALINK | REPORT

http://en.wikipedia.org/wiki/DDR3_SDRAM#Latencies

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BrokenLime + PM | QUOTE | PERMALINK | REPORT

[quote] Nv1d14 : @ Yuyulian. Thanks, but that doesnt answer my question. That doesnt say WHY higher speeds have higher latencies. @ BrokenLime. Ok, but why is that. Why does a higher bandwidth require more latency? [/quote] Regarding RAM in general (SDRAM, DDR, etc), higher clock rates mean a greater probability of bit corruption. Latencies are increased to prevent this. DDR3 latency is similar to DDR2 latency due to differences in design though.

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skye09 + PM | QUOTE | PERMALINK | REPORT

Latency with respect to time is shorter in the DDR3 interface than the DDR2 variant.

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Nv1d14 06/23/10 + PM | QUOTE | PERMALINK | REPORT

@ BrokenLime. Do you have a link to explain that better? I dont understand how higher speeds will cause bit corruption. @ Skye09. Youre wrong. The timings on DDR3 are clearly higher than on DDR2. Please dont post if you dont know what youre talking about.

skye09 06/24/10 + PM | QUOTE | PERMALINK | REPORT

[quote] Nv1d14 : @ BrokenLime. Do you have a link to explain that better? I dont understand how higher speeds will cause bit corruption. @ Skye09. Youre wrong. The timings on DDR3 are clearly higher than on DDR2. Please dont post if you dont know what youre talking about. [/quote] *sigh* If youre gonna respond, at least READ my post. But let me see if I can dumb this down so that even YOU can understand it. Contrary to popular belief, DDR3 has less latency than DDR2 with respect to time . That means, when measured in the proper time interval of nanoseconds, each cycle created by DDR3 vs DDR2 will be lower. CL is NOT measured in units of time, but rather in clock cycles. Latency is a measurement of time, Cas Latency is not, hence the illusion that DDR3 has more "latency" than DDR2, which it does NOT .

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