Why can't I get 1T command rate?

[big4x4]

With the setup below, I have always wondered why I cannot get my ram to run at 1t. Even at defaults it would never even post! Why is that?

 

[TC91]

i believe your ram frequency might be too high for 1T command rate (more voltage may help but that might also outright just fry your ram in the process), most high speed ram use 2T command rate anyways.

 

[LOUISSSSS]

my mb doesn't have an option for command rate. i heard a rumor saying the p35 chipsets don't have this option? is that true?
from what i know, it doesn't make much of a difference in speed anyway...

 

[Cheex]

That is correct, at least to the extent of my knowledge anyway...P35 chipsets do not have a 1T Command Rate setting.

However, IIRC, all nVidia chipsets, do.

 

[EarthwormJim]

My DFI P35 board has a 1T command setting. It doesn't post at it, but the option is there.

 

[Billb2]

Your memory controller won't handle the bandwidth of 1T;

Perhaps this will help:
The memory controller is like a doorway with a line of people going through. Like ticket takers at a sport stadium.
The doorway has an absolute limit on how many people can go through in any given time span.
Faster memory speed makes the line move faster.
More memory bandwith (1T) makes more lines of people.
Since the doorway is of limited capacity, people trying to go through too fast or too many lines of people will clogg up the doorway and piss off the people so they then decide to crash/lockup your computer or corrupt your hard drive.

The object of the game (for Intel and AMD) is to get as many people through the door way as fast as possible. Usually, with Intel DDR2 memory controllers, the ticket takers at the doorway are really fast, compaired to AMD DDR memory controllers. So speeding up the line (memory) is the most effective way to get more people through.
Since AMD ticket takers are slower, putting more ticket takers on the dorway (1T) works for AMD memory controllers.

That's not to say that with an intel memory controller you can't slow down the memory enough so that you could add more ticket takers, but that way there will still be less people going through than just speeding up the memory (line).

Some motherboards, due to their design, may be able to support higher bandwidth than others. Those manufactures with beter memory controlles just add the 1T option so that in case it can work, it's there.

 

[nerp]

1T vs. 2T was an oft-discussed topic when everyone was using DDR, not DDR2. With DDR systems, the performance difference between a 1T and 2T command rate were virtually unnoticable except in synthetic benchmarks. Trying to achieve a 1T command rate with DDR2 or 3 memory is more or less a pipe dream. And considering that memory timings are less important with DDR2 than DDR1, the difference between 1T and 2T is even less significant. And, recent tests have shown that there's very little difference between running memory with super tight timings and faster speeds as opposed to a lower speed and looser timings. Sure, Sandra might have some dramatic graphs but in real world usage and games, you're losing 1-5 FPS, max. It's all CPU speed these days so struggling to get better memory timings might be a waste of time and potentially frustrating for little benefit.

 

[Billb2]

Originally posted by: nerp
... performance difference between a 1T and 2T command rate were virtually unnoticable except in synthetic benchmarks.
...Trying to achieve a 1T command rate with DDR2 or 3 memory is more or less a pipe dream.

QFT x 2