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DDR3 1066MHz CL7 or DDR3 1333MHz CL9?
- Thread starter Araanor
- Start date
I think this is how it works, please correct me if I'm wrong:
Latency = how many clock cycles to respond, not how much time to respond
Operating frequency is how many clock cycles per second
Therefore the latency in time is the CAS latency divided by the clock frequency. Hence,
CL7 cycles @ 1066 megacycles/second = 7/1066= .0066 *10^-6 seconds or 6.6 nanoseconds
CL9 cycles @ 1333 megacycles/second = 9/1333= .00675 *10^-6seconds or 6.75 nanoseconds
Therefore with the higher clocked memory at looser timings you are barely slower on response and your throughput will be better. I don't know for fact this is correct but it seems logical to my mechanical brain.
Latency = how many clock cycles to respond, not how much time to respond
Operating frequency is how many clock cycles per second
Therefore the latency in time is the CAS latency divided by the clock frequency. Hence,
CL7 cycles @ 1066 megacycles/second = 7/1066= .0066 *10^-6 seconds or 6.6 nanoseconds
CL9 cycles @ 1333 megacycles/second = 9/1333= .00675 *10^-6seconds or 6.75 nanoseconds
Therefore with the higher clocked memory at looser timings you are barely slower on response and your throughput will be better. I don't know for fact this is correct but it seems logical to my mechanical brain.
Mike Clements
Gone but not Forgotten
- Joined
- Oct 31, 2006
- Messages
- 2,049
If you plan to run stock speeds on the CPU, then get the CAS7 memory. However, if you expect to attempt to get a good CPU OC and higher memory speeds, get the 1333 kit.
In a nutshell, don't buy memory that will bottleneck your CPU OC.
In a nutshell, don't buy memory that will bottleneck your CPU OC.
I think my comments and Mike's can both be true. However what he is saying is more practically useful. If you are not OCing, then just get RAM to match what your CPU runs at stock.
From [H]s AM3 with DDR3 review http://www.hardocp.com/article.html?art=MTYyMSwsLGhlbnRodXNpYXN0it seems that the CPU bus and the memory bus are completely independent of each other. In this case your memory will not limit your CPU OC at all. If you don't do anything the memory should run at the SPD values. If this is the case I would recommend the 1333 CAS9 due to the time latencies I showed in my earlier post.
That being said I will know more in a week when my ASUS M4A79T Deluxe gets here so I can play with the 720 BE CPU that got here today. I got Corsair XMS3 1600 with the CAS9 for my system.
From [H]s AM3 with DDR3 review http://www.hardocp.com/article.html?art=MTYyMSwsLGhlbnRodXNpYXN0it seems that the CPU bus and the memory bus are completely independent of each other. In this case your memory will not limit your CPU OC at all. If you don't do anything the memory should run at the SPD values. If this is the case I would recommend the 1333 CAS9 due to the time latencies I showed in my earlier post.
That being said I will know more in a week when my ASUS M4A79T Deluxe gets here so I can play with the 720 BE CPU that got here today. I got Corsair XMS3 1600 with the CAS9 for my system.
jakethesnake011
Limp Gawd
- Joined
- Apr 15, 2009
- Messages
- 163
I agree with Mike myself, if stock lower Case, if overclocking higher frequecny