Latencies in DDR3
Last response: in Memory
Hi guys & girls ::- ).
Could you link me to a good article explaining latencies in DDR 3?
Is 9-9-9-27 better than 7-7-7-20? I thought not. I thought the lower the latency the better. But then I found that the 7-7-7-20 module is cheaper ::- /.
DDR 3 latencies also seem to be greater than DDR 2. *sigh*. Maybe somebody very knowledgeable around here can explain all this latency stuff in a few short sentences? ::- ).
Thank you!
P.S.: in the meantime, I will read this area's "Sticky" post with Memory FAQ, but it is pretty dense. Also I hope you'll be able to clear me up on that latency issue I described above.
Could you link me to a good article explaining latencies in DDR 3?
Is 9-9-9-27 better than 7-7-7-20? I thought not. I thought the lower the latency the better. But then I found that the 7-7-7-20 module is cheaper ::- /.
DDR 3 latencies also seem to be greater than DDR 2. *sigh*. Maybe somebody very knowledgeable around here can explain all this latency stuff in a few short sentences? ::- ).
Thank you!
P.S.: in the meantime, I will read this area's "Sticky" post with Memory FAQ, but it is pretty dense. Also I hope you'll be able to clear me up on that latency issue I described above.
More about : latencies ddr3
Axonn, if comparing just the latencies, then yes - the lower, the better. However, everyone knows that RAM quality isn't measured by just latency; and the price of RAM should never be a means of quality measurement.
While the typical latencies for DDR2 were 5-5-5-15, the standard latencies for the DDR3 are 7-7-7-20 for DDR3-1066 and 7-7-7-24 for DDR3-1333.
DDR3 latencies are numerically higher because the I/O bus clock cycles by which they are measured are shorter; the actual time interval is similar to DDR2 latencies (around 10 ns). As with earlier memory generations, faster DDR3 memory became available after the release of the initial versions. DDR3-2000 memory with 9-9-9-28 latency (9 ns) was available in time to coincide with the Intel Core i7 release. CAS latency of 9 at 1000 MHz (DDR3-2000) is 9 ns, while CAS latency of 7 at 667 MHz (DDR3-1333) is 10.5 ns.
Consider this equation:
CAS ÷ Frequency (MHz)) × 1000 = X ns
(7 ÷ 667) × 1000 = 10.4948 ns
While the typical latencies for DDR2 were 5-5-5-15, the standard latencies for the DDR3 are 7-7-7-20 for DDR3-1066 and 7-7-7-24 for DDR3-1333.
DDR3 latencies are numerically higher because the I/O bus clock cycles by which they are measured are shorter; the actual time interval is similar to DDR2 latencies (around 10 ns). As with earlier memory generations, faster DDR3 memory became available after the release of the initial versions. DDR3-2000 memory with 9-9-9-28 latency (9 ns) was available in time to coincide with the Intel Core i7 release. CAS latency of 9 at 1000 MHz (DDR3-2000) is 9 ns, while CAS latency of 7 at 667 MHz (DDR3-1333) is 10.5 ns.
Consider this equation:
CAS ÷ Frequency (MHz)) × 1000 = X ns
(7 ÷ 667) × 1000 = 10.4948 ns
Here is the definition of CAS/Latency... http://en.wikipedia.org/wiki/CAS_latency
Basically, the lower the CAS the faster the RAM will process data based the DDR level. It is independant of the MHz to a point. Examples, DDR3 is faster than DDR2, DDR3 1333 Cas6 is faster than DDR3 1600 Cas9... etc.
Basically, the lower the CAS the faster the RAM will process data based the DDR level. It is independant of the MHz to a point. Examples, DDR3 is faster than DDR2, DDR3 1333 Cas6 is faster than DDR3 1600 Cas9... etc.
Related ressources
- Can You Mix DDR3 Memory Latencies ? - Forum
- Mixing ram with different latencies - Forum
- BIOS chip damaged by mixing RAM of differing latencies ??? - Forum
- DDR2-533: Extra Latencies ? So what? - Forum
- 4gb vs 8gb but different latencies ! - Forum
Hello T_T, tecmo34, thank you for answering ::- ).
T_T: what I found was a 7-7-7-20 with a 1333 module. I suppose this is good ::- ). This ones:
http://www.webhallen.com/hardvara/113568-kingston_hyper...
Do you recommend buying higher than 1333 modules? Intel says that Core i5 (for example) uses 1066 to 1333.
T_T: what I found was a 7-7-7-20 with a 1333 module. I suppose this is good ::- ). This ones:
http://www.webhallen.com/hardvara/113568-kingston_hyper...
Do you recommend buying higher than 1333 modules? Intel says that Core i5 (for example) uses 1066 to 1333.
Related ressources:
- ForumPERFORM THESE STEPS before posting about boot problems
- ForumCPU-memory latency DDR3
- ForumCore i7 2600 Support 1600MHz DDR3 memory
- ForumDDR3 with a Cas Latency of 4 or 1?
- ForumDifference between DDR2 and DDR3
- ForumLatency: 9-9-9-24 ddr3
- ForumWhat is/are the fastest, best DDR3 RAMs out there?
- ForumWhat is the best DDR3 Memory Upgrade I can to? PC3-12800 or PC3-10600
- ForumASRock 970 Extreme3 fails to notice DDR3 1600 despite BIOS settings
- ForumWhich is better memory
- ForumDdr3 1333runnig at 800mhz
- ForumWarming don't use intel ddr3 ram on amd system!!!
- Forum[Solved] Need advice on 4GB of DDR3 RAM :/
- ForumCan one use ddr3 12800 instead of 10600?
- ForumDecent, lower-priced DDR3 RAM for this EVGA Mobo?
- More resources
Read discussions in other Memory categories
!
