I dont understand memory timings 4-4-4-12 5-5-5-15

I know what values are supposed to be 4-4-4-12 or 5-5-5-15 when OC'ing but thats only half of the values that I can actually modify in my DRAM settings, do I leave the rest of them to automatic????

Also whats the difference between 1T and 2T timing?

I have a:

MSI P6N SLi 650i chipset
E6400 C2D 2.13Ghz
OCZ 2GB (1GBx2) PC6400
650w Antec PowerTrio
eVGA 8800GTX
35 answers Last reply
More about dont understand memory timings
  1. Quote:
    I know what values are supposed to be 4-4-4-12 or 5-5-5-15 when OC'ing but thats only half of the values that I can actually modify in my DRAM settings, do I leave the rest of them to automatic????

    Also whats the difference between 1T and 2T timing?

    I have a:

    MSI P6N SLi 650i chipset
    E6400 C2D 2.13Ghz
    OCZ 2GB (1GBx2) PC6400
    650w Antec PowerTrio
    eVGA 8800GTX


    The first four timings you mentioned are the important ones, the first three are key (4-4-4) or (5-5-5). Lowering the value tightens the RAM's performance, increasing the value loosens the RAM's responsiveness. Beyond the first four settings auto works fine in most cases, the difference is not that great beyond those first 3 settings. The CAS LAT is the most noticable when put to practical use.
  2. what about 1T and 2T Timing? I still dont understand the meaning to them.

    So leave the others at AUTO?
  3. Quote:
    what about 1T and 2T Timing? I still dont understand the meaning to them.

    So leave the others at AUTO?


    The others will respond to lowering or increasing the value, but not so much as those first three settings. They are the important ones. I wish I could give you a definative, scientific answer to the 1T/2T question, but I don't have time to research it now. 1T is a time setting the RAM will perform at that offers a faster mode of operation than 2T. 1T is good if your sysyem can do 1T. If not 2T will suffice just fine.
  4. but for a lack of better definition 1T is faster than 2T?
  5. Quote:
    but for a lack of better definition 1T is faster than 2T?


    Yes. The ram performs it function with the CPU faster a 1T than 2T. Simple. The difference is not like from here to the moon.
  6. interesting

    thanks for the advice d00d!

    appreciate it :D
  7. Quote:
    interesting

    thanks for the advice d00d!

    appreciate it :D


    You're welcome. So loosen up those timings and clock that processor higher. Or tighten 'em up and give your system's bus a break! :D
  8. So if I tighten them up how does it give the system bus a break? lol

    I'm so confused I feel like a n00b
  9. Quote:
    So if I tighten them up how does it give the system bus a break? lol

    I'm so confused I feel like a n00b


    If you are not overclocking your FSB and your RAM is rated at 4-4-4 then you should be able to set it there in BIOS and run the tighter, more responsive timings. If you are overclocking your FSB and your processor has hit a wall, by loosening the timings to 5-5-5 you could get a little more fsb and processor speed by loosening the timings.

    If your RAM will boot up and run stable at 4-4-4 your good. I was just taking a stab at your questions when I said to loosen up the timings and overclock away.
  10. cool thanks
  11. So, if Im running my CPU stock, and I tighten my settings on my RAM, this will increase responsiveness?
    My Corsair XMS2 PC2-6400 is rated 5-5-5-18 2T stock but this is at 1.8V. The optimal timings of 4-4-4-12 2T required 2.1V. I bumped my DRAM voltage to 2.1 and then changed only the CAS LAT to 4 first. It booted so I went back and changed the RCD, RP and TRAS. It seems to be running stable so far. Everest and CPU-Z show the changed timings.
    So, given that, what should I expect beyond synthetic memory testing?
    Thanks.
  12. Quote:
    So, if Im running my CPU stock, and I tighten my settings on my RAM, this will increase responsiveness?
    My Corsair XMS2 PC2-6400 is rated 5-5-5-18 2T stock but this is at 1.8V. The optimal timings of 4-4-4-12 2T required 2.1V. I bumped my DRAM voltage to 2.1 and then changed only the CAS LAT to 4 first. It booted so I went back and changed the RCD, RP and TRAS. It seems to be running stable so far. Everest and CPU-Z show the changed timings.
    So, given that, what should I expect beyond synthetic memory testing?
    Thanks.


    PC6400 with a 1.8v default is kind of scarce and not the norm. 2.0 to 2.1 is more the norm for PC6400. I didn't know Corsait gave 1T/2T ratings. So your Corsair DIMMS are running at 4-4-4-12. Cool. I can tell the difference if my systems are running at 4 CAS LAT or say a looser 5 CAS LAT. Apparently you can not and that is understandable. Be careful overvolting your RAM. You can cause you system to run hot and possibly even burn out your DIMMS. 2.1 sounds fine.
  13. Just out of morbid curiousity why would anyone want to change the voltage to like 2.80? lol
  14. It is only DDR2 that runs at the lower voltages. I run a lot of PC3200 at 2.6-2.7v.
  15. whats the science behind DDR2 running at lower volts?

    New and improved technology?
  16. Yeah, amazing PC6400 transfers data at 6.4 GB/sec while PC3200 transfers at 3.2 GB per/sec., twice as fast using less voltage (power) to do so. Exactly why...you are elected to do the research this time.
  17. hehe will do, got nothing better to do while at work.

    thanks for all the advice
  18. You are going to dig up all kinds of fantastic stuff! Let me in on what you find!
  19. The only thing Im nervous about is what the stock DIMM voltage was. In BIOS, it shows +0.1 and so on in green. The +0.3 is yellow, so I assume Im still in the safe range. Now, if Everest says the the timing is 5-5-5-18 @1.8V, am I to assume that the DIMM voltage is the same?

    K. Found out stock memory DIMM voltage is 1.8V. Bumped it +0.3V. It's a good board so I think it'll handle it fine. Is there a way of stressing it?
  20. Look up the recommended voltage setting at your RAM mfg. website. If your board defaults the volyage to 1.8v. it is ok to increase the voltage to mfg. specs. If you are at 5-5-5 and can adjust to 4-4-4 in BIOS that's fine. Bumping the voltage to the mfg. recommended voltage could help in getting to 4-4-4-12 timings. Mem Test 86 will stress test it. Google it.
  21. Quote:
    but for a lack of better definition 1T is faster than 2T?


    Yes it is faster.
    T-1/CR-1 FTW.
  22. Hm, all this voltage talk makes me wonder about my own voltages!

    I have the GA-965P-DQ6 board, and my RAM is also defaulted at 1.8v (DDR2-6400). It runs perfect at 4-4-4-12 timings at that voltage. I bring it up to the recommended 2.1v and the BIOS warns me of overvoltage. Is this just a setting in the BIOS that makes it warn me, or does it actually test the voltage to determine it's too much? I don't want to burn out my RAM. And, if it's working fine with 1.8v at 4-4-4-12, should I even consider bumping it up to 2.1v?
  23. Quote:
    Hm, all this voltage talk makes me wonder about my own voltages!

    I have the GA-965P-DQ6 board, and my RAM is also defaulted at 1.8v (DDR2-6400). It runs perfect at 4-4-4-12 timings at that voltage. I bring it up to the recommended 2.1v and the BIOS warns me of overvoltage. Is this just a setting in the BIOS that makes it warn me, or does it actually test the voltage to determine it's too much? I don't want to burn out my RAM. And, if it's working fine with 1.8v at 4-4-4-12, should I even consider bumping it up to 2.1v?


    Good question. Bumping from 1.8v to 2.1 is going create heat at the least. If your RAM mfg. specs state 2.1v that means the company has tested it to run properly at that level. I would think the performance of the voltage regulators on your MB have a lot to do with accuracy and adjustability and accuracy of the MB voltages.
  24. Quote:
    So, if Im running my CPU stock, and I tighten my settings on my RAM, this will increase responsiveness?
    My Corsair XMS2 PC2-6400 is rated 5-5-5-18 2T stock but this is at 1.8V. The optimal timings of 4-4-4-12 2T required 2.1V. I bumped my DRAM voltage to 2.1 and then changed only the CAS LAT to 4 first. It booted so I went back and changed the RCD, RP and TRAS. It seems to be running stable so far. Everest and CPU-Z show the changed timings.
    So, given that, what should I expect beyond synthetic memory testing?
    Thanks.


    One setting will finnish a transfer in 18 cycles and the other in only 14...if you had the same "speed" ram but running @ 3.4.4.8 then you would use half the cycles to move the same amout of data.

    Just use Everest and run the memory test with both settings and you will see the boost in lower time settings.
    If it will run @ T-1/CR-1 you will see another boost (more so with AMD).

    I am still using DDR1 ram but 260Mhz @3.4.4.8 (DDR-520) rather than 200Mhz @2.2.2.5 and Everest puts my read/write/copy transfers way above DDR2-800.
  25. i am still confused about the timings ....as i understand 4-4-4 is better than 5-5-5 and it is logical in terms of responsiveness ..i mean 4 millisecond is faster for sure than 5 millisecond.....but how come u say that u get 5-5-5 when overclocking since over clocking means better boost to the system....i mean if someone told me that a 4-4-4 ram is overclocked i would say the new timing would be 3-3-3 since it is better responsiveness and faster....not 5-5-5!!!

    please can someone explain to us about this???
  26. The confusion arises from the fact that we normally measure latency timings in clock ticks. When overclocking, we are (hopefully) increasing the clock frequency, so the same absolute latency time now takes up more clock ticks. For example, CL4 (4 clock ticks) at DDR2-800 is the same amount of time as CL5 (5 clock ticks) at DDR2-1000.
  27. Quote:
    PC6400 with a 1.8v default is kind of scarce and not the norm. 2.0 to 2.1 is more the norm for PC6400.


    Better be careful what you're considering default, 1.80V is THE specification for DDR2 DIMMs. Everything higher is an overclocking value.

    Default voltage is the one you boot up at. Default voltage is 1.80V. "Normal" DDR2-800 has higher specified voltage, because "Normal" DDR2-800 is comprised of overclocked, slower parts.
  28. Ok. I just bought the Adata PC6400 2 GB kit (mfg. specs 1.8v.) on Newegg for a micro board that has adjustments of 1.8 and 1.9v in BIOS only. If I had thought, my G. Skill PC6400 in RMA currently rated at 2.0-2.1v would have worked just fine. So I can run my PC6400 at 1.8v. or if need be for overclocking or performance enhancements I can safely go to the 2.1v. mfg. specs?
  29. Considering i have (A8N32 - SLI DELUXE) mobo.....

    is buying those two sticks together in dual channel better(3-4-4-8)?
    http://www.amazon.com/Corsair-XMS-memory-184-pin-TWINX2048-3200/dp/B0002KK41I/ref=sr_1_5/102-7748109-0464131?ie=UTF8&s=electronics&qid=1177477036&sr=1-5
    putting in mind i would buy another same two sticks in future when going to 64 edition either for xp or vista so 4GB in total

    or buying three sticks of the following ram model better (2-3-3-6 for each module) as it says in specs?
    http://www.amazon.com/Corsair-XMS-Memory-184-pin-PC3200/dp/B0006ODZ1Q/ref=pd_bbs_sr_1/102-7748109-0464131?ie=UTF8&s=electronics&qid=1177477036&sr=1-1
    putting in mind i would stay with 32 edition either xp or vista

    waiting for your good support
    :roll:
  30. Quote:
    i am still confused about the timings ....as i understand 4-4-4 is better than 5-5-5 and it is logical in terms of responsiveness ..i mean 4 millisecond is faster for sure than 5 millisecond


    The RAM timings you mentioned including RAM CAS Latencys are just that RAM timings, not overclockings.

    Quote:
    but how come u say that u get 5-5-5 when overclocking since over clocking means better boost to the system


    Confusion on your part. No one said you get 5-5-5 when overclocking. When overclocking, reducing tight 4-4-4 timings to a looser 5-5-5 timing may allow for continuing with the attempt at higher and higher FSB/CPU overclocking. Loosening the timing to 5-5-5 may allow the CPU to be overclocked higher. The RAM and CPU work together, but have various ways of being adjusted and independently so of one another.

    Quote:
    i mean if someone told me that a 4-4-4 ram is overclocked


    Because it is 4-4-4 it is not overclocked. adjusting the RAM's frequency (speed) form say 800 mhz. to 1000 mhz. is overclocking the RAM. 4-4-4 to 5-5-5 is not overclocking.

    Quote:
    i would say the new timing would be 3-3-3 since it is better responsiveness and faster....not 5-5-5!!!


    The RAM timings (CAS Lat 4-4-4-12 etc.) are an entirely different thing than the speed (800 mhz. 1000 mhz PC6400, PC8500 etc.) of your RAM. You have these two factors or characteristics of RAM confused. HTH.
  31. first i would like to thank u for ur explanation since it removed lots of confusion i had before.

    lastly , if someone can help me with my last reply i posted and which option i should go for?
  32. You're welcome. Just keep practicing and learning. Read up on RAM adjustments, how RAM works and hone your skills by trial and error. I don't know much, I just fool around with a lot of computers all the time and pick up what I can. It's a great hobby.
  33. Quote:
    So I can run my PC6400 at 1.8v. or if need be for overclocking or performance enhancements I can safely go to the 2.1v. mfg. specs?


    The manufacturer specifies a "guaranteed stable overclock" value of a certain speed/latency at a certain nonstandard voltage. Under-latency is a form of overclocking, even though it's not the clock rate that's affected (latency is in cycles, based on the clock rate, etc).
  34. leo2kp said:
    Hm, all this voltage talk makes me wonder about my own voltages!

    I have the GA-965P-DQ6 board, and my RAM is also defaulted at 1.8v (DDR2-6400). It runs perfect at 4-4-4-12 timings at that voltage. I bring it up to the recommended 2.1v and the BIOS warns me of overvoltage. Is this just a setting in the BIOS that makes it warn me, or does it actually test the voltage to determine it's too much? I don't want to burn out my RAM. And, if it's working fine with 1.8v at 4-4-4-12, should I even consider bumping it up to 2.1v?



    Here's the deal with the voltages, its just like your cpu when overclocking. Increase the Hz / frequency and it speeds up but becomes more unstable, you decrease instability by increasing voltage. Now all that relates to more heat. Yes, you can burn up your ram, so if you go to overclocking sites and the such you will see all kinds of cooling systems for your ram, special heat spreaders and fans built right on top of the ram sticks, etc.. speed increase = freq increase, = instability = a need to increase voltage to maintain stability = special cooling to prevent scorching your hardware. Exact same rules for overclocking the cpu. But.. there is a relationship between overclocking the Base clock vs. just overclocking the FSB and ram. Do a little reseach and you'll find a DIY page that will explain it all in much more detail.
  35. badge said:
    Quote:
    i am still confused about the timings ....as i understand 4-4-4 is better than 5-5-5 and it is logical in terms of responsiveness ..i mean 4 millisecond is faster for sure than 5 millisecond


    The RAM timings you mentioned including RAM CAS Latencys are just that RAM timings, not overclockings.

    Quote:
    but how come u say that u get 5-5-5 when overclocking since over clocking means better boost to the system


    Confusion on your part. No one said you get 5-5-5 when overclocking. When overclocking, reducing tight 4-4-4 timings to a looser 5-5-5 timing may allow for continuing with the attempt at higher and higher FSB/CPU overclocking. Loosening the timing to 5-5-5 may allow the CPU to be overclocked higher. The RAM and CPU work together, but have various ways of being adjusted and independently so of one another.

    Quote:
    i mean if someone told me that a 4-4-4 ram is overclocked


    Because it is 4-4-4 it is not overclocked. adjusting the RAM's frequency (speed) form say 800 mhz. to 1000 mhz. is overclocking the RAM. 4-4-4 to 5-5-5 is not overclocking.

    Quote:
    i would say the new timing would be 3-3-3 since it is better responsiveness and faster....not 5-5-5!!!


    The RAM timings (CAS Lat 4-4-4-12 etc.) are an entirely different thing than the speed (800 mhz. 1000 mhz PC6400, PC8500 etc.) of your RAM. You have these two factors or characteristics of RAM confused. HTH.



    For newbies think of it this way... if using 800 ram you have ta CAS Latency of 4 and are stable, you increase the bus freq to 1000 well because the clock ticks are coming faster, you will get 5 clock ticks counted in the same realtime timeframe. now there is a physical limitation to just how fast your ram is going to go. That 4 before is now 5 with the new clock settings. You may think the ram is slower but it is not the Cas Lat is actually the same, but the overall execution of the ram is executing at 20% faster, and if you were able to keep the other settings a 4's then not only is the ram executing at 20% faster rates but the 'access' time to the columns and rows are triggering at a faster pace with the same setting,,, so you are accessing the locations and processing the information at a greater rate of speed... There's a little bit to it to understand. When you start overclocking, try moving one value at a time and then check system for stability under stress. if all is stable make an adjustment and keep going... you'll get to a point where the system won't be stable... you then just back off that setting and try another, when adjustments are tweaked as tight as they can go and remain stable...ONLY then do you increase the voltage a bit,,, and give your tweaks another go and see if you can make up more ground..lather, and rinse, repeat as many times is necessary... all the while making sure you have high performance cooling if needed to allow you to go into this territory of speed and voltage ranges, if you don't,, you'll tweak yourself into burned up ram or something else.. I'd recommend trying your hand at overclocking on an old rig and not your primary use computer until you get the hang of it. Use a variety of benchmarking software to measure your performance increases after you've gone as far as you can. keep a note pad handy and write down all your changes in a sequence log and note any anomalies... its fun but one must be patient... you can wire tie a case fan right over your ram sticks. Or you can get silly and go chilled and submerged like my son and i are going to do together. 10 gal fish tank, board submerged in non conductive transformer oil, aquarium pumps move oil to small dorm room refrigerator with heat exchanger inside then pushes cold oil back to tank...then we seal that tank inside a 15 gal tank with a nitrogen layer and seal it...condensation you know is a bitch.. all so we can get cold to overclock the he double hockey sticks out the beast.... include a neon light and a bubbler and you've got a really interesting show piece.
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