tRAS asynchronous?

Kilobyte Kid

tRAS asynchronous?



I would like to ask you for the explanation, how is it with the memory timings.


According to this and this explanations, it seems that the tRAS should be a whole multiple of the tCAS or tCAS+tRCD. But in this Crucial module, it isn't so.


Because I understand, that Wikipedia is not always perfectly expertised, I am asking here. Would anybody from Micron (or anyone else) explain?


By the way, which combination of timings should be 'faster', 10-10-10-28 or 11-11-11-27? The explanations are kind of confusing. And also, why are they all so 'slow', if the standard reckons even with 8-8-8 timings?


Thanks for your answers in advance!


Best to everyone

3 Replies

Re: tRAS asynchronous?




The explanations you see are fine in respect of standard memory, however you can also get performance memory where the timings are tighter to give that better performance so it may not follow the general rule.  The parts you are looking at are our Ballistix performance memory so they are designed to allow you to get the most out of your system.  Although they may seem 'slow' with higher timings compared to other modules, these timings are not the only thing you have to consider; you should also take into account the actual MHz speed, voltage & of course the amount of megabytes all which will have a significant increase on performance.  If you plan on upgrading with Ballistix, you should consider that your entire system configuration will need to support certain settings or configuration values, which may require manually changing the BIOS setup. You may also need to adjust voltage, timings, speed, and other settings.

Please refer to your operating manual for details on configuration and supported BIOS values; specific system performance may vary and unsupported configurations may revert to industry-standard or system defaults. Overclocking (running your system faster than published speed) or otherwise modifying your system timing may result in damage to computer components. If you plan to operate your hardware outside of specifications, do so at your own risk.

I hope this helps.


Maulmod, Crucial Moderator UK

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Kilobyte Kid

Re: tRAS asynchronous?

Hi, Maulmod,


thanks for your answer!


Actually, the module I linked to, is from the Ballistix Sport series, which promises the following:


"Unlike traditional Ballistix products, those industry-standard specifications require no special or tricky BIOS configuration." (See the 'Product details' tab).


As I understand it, 'industry-standard' should stand for JEDEC specs. preprogrammed in the SPD (1.5 V, 800 MHz - as for DDR3) - with no tweaking required. To be honest, I am really not going to be limed to overclocked fakes (1333 MHz chips, promising 1600 MHz). That is, what I find to be a SCAM.


Indeed, I am quite disappointed that a professional company like Micron shrinks to such marketing techniques. I am really sorry to see this (in the Ballistix - non-Sport - marketing-range).


I was actually asking on the STANDARD, not what is possible or impossible. In overclocking nearly everything is possible - even totally senseless things like running FSB and RAM non-symmetrically (out of time), which, in my opinion, only messes up the cache memories of the CPU (the data cannot travel, must wait for the next cycle and the system freezes up).


Best regards

Kilobyte Kid

Re: tRAS asynchronous?

I found the answer.


It is in the JEDEC Standard No. 79-3E (page 142, 153 in PDF).


The tRAS for DDR3-1600 is always 28 cycles, whilst the other values (tCL, tRCD and tRP) vary between 8-8-8 and 11-11-11, but should be equal (no combinations allowed, as by the standard).


Hope it helps others, too.




P.S. Watch out for modules, requiring voltage higher than the standard 1.5 V. These use lower speed (frequency and latencies) chips and promise a higher speed, but this is only achieved after overclocking (e.g. 1333 becomes 1600, CL = 11 becomes CL = 7 etc.). Serious producers at least state this in the documentation (SPD settings); otherwise it is recognized after installing and letting the BIOS set values automatically (uses SPD data record).