Memory timing question

[xblackdemonx]

Hi, i was wondering about the memory timing

I heard that the timing is more important than the speed. Does that mean that ill get more performance with 2GB DDR-400 2-2-2-5 vs 2GB DDR3-1333 9-9-9-27 ?

:roll:

Thanks

 

[badge]

Hi, i was wondering about the memory timing

I heard that the timing is more important than the speed. Does that mean that ill get more performance with 2GB DDR-400 2-2-2-5 vs 2GB DDR3-1333 9-9-9-27 ?

:roll:

Thanks

I heard that the timing is more important than the speed.

The speed is far more important than the timing. Speed in mhz. determines the data transfer rate between RAM and CPU. Timing adjusts the responsivness of the RAM, not the Data transfer rate.

Does that mean that ill get more performance with 2GB DDR-400 2-2-2-5 vs 2GB DDR3-1333 9-9-9-27 ?

Adjustment for speed and timing can be made in BIOS. RAM running at 400 mhz. (3.2 GB/sec. transfer rate) is much slower than memory running at 1333 mhz (10.6 GB/sec. transfer rate).

The answer to your question becomes obvious.

3.2 GB/sec. data transfer rate compared to 10.6 GB/sec transfer rate.

 

[Mondoman]

Although badge is mostly right, timings can make a difference for two main reasons:
1) Throughput (MHz) is limited by the FSB speed, since all data to/from memory has to go through the FSB. Current Intel C2D CPUs mostly have a standard 1066MHz FSB data transfer rate, which can be saturated by a pair of DDR2-533 DIMMs running in dual-channel mode.
2) Not all memory accesses are sequential. Many of the latency values have a bigger effect on non-sequential accesses.

Here's some data so you can decide for yourself what's best:
http://www.madshrimps.be/?action=getarticle&number=1&artpage=1962&articID=472

 

[badge]

Although badge is mostly right, timings can make a difference for two main reasons:
1) Throughput (MHz) is limited by the FSB speed, since all data to/from memory has to go through the FSB. Current Intel C2D CPUs mostly have a standard 1066MHz FSB data transfer rate, which can be saturated by a pair of DDR2-533 DIMMs running in dual-channel mode.
2) Not all memory accesses are sequential. Many of the latency values have a bigger effect on non-sequential accesses.

Here's some data so you can decide for yourself what's best:
http://www.madshrimps.be/?action=getarticle&number=1&artpage=1962&articID=472

2) Not all memory accesses are sequential. Many of the latency values have a bigger effect on non-sequential accesses.

OP's question referred to the idea that RAM (PC3200) performing at 3.2 GB/sec data transfer rate could outperform another RAM (PC10600)performing at 10.6 GB/sec data transfer rate 'because' the first one is CAS 2 while the latter is CAS 9. I pointed out the difference in the speed at which data is transfered.

This information is a bit dated (and certainly simple and straightforward), but it may shed light on the question of performance difference between the varying CAS latencies of RAM.

What is CAS latency?

CAS latency (also referred to as latency) is the amount of time it takes for your memory to respond to a command. Specifically, it is the length of time between memory receiving a command to read data, and the first piece of data being sent from the memory.

What is the performance difference between CL2 and CL3?

CL2 DIMMS process data a little quicker than CL3 DIMMS in that you have to wait one less clock cycle for the initial data. However, after the first piece of data is processed, the rest of the data is processed at equal speeds. Latency only affects the initial burst of data. Once data starts flowing, there is no effect.

Although this is very basic defination, I just hope this helps in answering OP's question.

 

[xblackdemonx]

ya, i understand both of your points, the MHZ is important but the timing is also as important.

in the picture: http://www.madshrimps.be/articles/IntelCore2Ishighspeedmemoryworththecost-jmke-13140.png

you can see that the 533(3-3-3-8) outperforms the 667 at (4-4-4-12) and (5-5-5-15) and its almost as good as the 667 (3-3-3-8)

ya i guess what im gonna do is im gonna check what is the highest MHZ i can set on my ram, ill do a benchmark, then im gonna try to set it to default MHz but with the lower possible latency and ill do another benchamrk to see the difference ...

Thanks

 

[badge]

Cool pic of...'the RAM god?' :lol:

 

[xblackdemonx]

lol ya

 

[Mondoman]

BTW, I just noticed that the OP is using an AMD system. Since the skt 939 and skt AM2 systems have the memory controller built into the CPU, there is no FSB in such system, and hence no FSB bottleneck. Thus, my point (1) only applies to current Intel-based systems.

 

[speed4life]

I wouldn't even worry about DDR3 for at least another year. Just get yourself some good DDR2 like DDR2 800 and overclock the frick out of it. Just make sure they have micron D9 chips in them.