Overclocking Your Rig 3 (RAM)

Discussion in 'Mods, Guides & Overclocking' started by mojo, Jul 29, 2005.

  1. mojo

    mojo New Member

    Overclocking Your Rig 3 (Memory)

    Finally, we are seeing people overclocking their components on GAMERS more than ever. This guide on overclocking Memory was promised a while ago, but IMO, the timing couldn't be better since we have members already overclocking Memory and confusing the younguns with all those numbers.

    First of all, much like FSB on a CPU, the higher the speed (in MHz) that your memory is clocked at is a very good estimate of how high your memory performance. However, this is not the only number of concern when overclocking memory.

    Here are some explanations for some of the other important memory parameters that should be considered to determine performance.

    CAS - CAS latency is the number of clock cycles between the memory receiving a "read" command and actually starting to read.

    RAS/Row Precharge or Row Address Strobe (Trp) - This Precharge to Active timing controls the length of the delay between the precharge and activation commands.

    RAS-to-CAS Delay (Trcd) - This timing controls the length of the delay between when a memory bank is activated to when a read/write command is sent to that bank.

    Row-active-delay (Tras) - The Active to Precharge timing controls how soon after activation the access cycle be started again.

    CPC: This is the delay between when a IC is selected and the time commands can be issued to the IC. The more chips on a module (Single vs. double sided) the more difficult it is for the memory controller to do this in 1 command clock. Most quality modules with an A64 Processor can do 1T rates on 256 and 512mb modules. 2T can increase your overclock but at a substantial loss in bandwidth.
    Typical Settings: 1T,2T

    These timings might sound like nonsense to some of us, but just remember, the lower these values, the better the performance since there is less delay between cycles.

    Also in order to get better timings, higher DIMM Volage is usually required.

    Example of very good memory timings for PC 3200 RAM running @ 200MHZ (DDR 400):
    CAS Latency: 2
    RAS/Row Precharge (tRP): 2
    RAS-to-CAS Delay (tRCD): 2
    Row-active-delay (tRAS): 5
    CPC: 1T

    thus is usually written 2-2-2-5-1T

    Recently, since the release of 90nm AMD Athlon 64 CPUs, It was realized that these CPUs could overclock to significantly higher fsb than 200MHz. Memory manufacturers have also introduced modules which are pre tested to guarantee that they will be stable @ uber high frequencies and uber lower latencies.

    We have noticed that Corsair and G Skill are now using Samsung TCCD RAM chips in order to achieve speeds of 300MHz! with 2.5-4-4-8 @ 2.6-2.7V. This is quie good, but still does not take advantage of memory timing tweaks.

    We have also seen Mushkin redline series and OCZ performance memory modules that can also clock @ decent speeds around 250MHz with 2-2-2-8 timings. To achieve these timings, often 3.3V is required. With this type of Voltage, TCCD just cries and says no. OCZ and Mushkin also have 300MHz modules which run @ similar timings to TCCD RAM based modules.

    The million dollar question, which is more important? timings or MHz?

    Well, I am not going to show u benchmarks that clarify this, instead I will simply say that:

    1) Higher MHz gives your more MHz overclockability for your CPU.

    2) At extremely high MHz, better timings are not yet possible and Memory performance is still around he same as lower MHz with better timings.

    Hope you all enjoy this guide. Your input would be greatly appreciated.

    *EDIT*
    ADVANCED SETTINGS FOR AMD SOCKET 939 DUAL CHANNEL MEMORY
     
  2. bushman

    bushman New Member

    failed to mention 1t Tmings vs 2t and a Whole lot of otehr stuff
     
  3. PhoeniX

    PhoeniX New Member

    i think this is really kool :)
     
  4. mojo

    mojo New Member

    Point taken bushman. I added in the Command per clock(CPC) aka command rate value in the original post.

    I agree that there a lot more tweaking settings available for A64 platforms than other systems. I am trying to keep this guide generalized and I would probably do another guide specifically for Athlon 64 CPUs.
     
  5. Paradoxxx

    Paradoxxx New Member

    Although some stuff is missing im sure it will trickle out... eg finding the best timing for your system... I normal go on anandtech and look for a similar setup to mine... they have usually have a chart with the different timings and the bandwidth achieved...

    Sometimes 2-2-2-7, 2-2-2-6 and 2-2-2-5 all give the same throughput. (flame me if im wrong)

    Nice comment

    The great balance between timing and mhz... Like we slowly becoming one happy OCing family.
     
  6. cereal_killer

    cereal_killer New Member

    now if i can only convince my self to overclock my pc

    and good job with guide to ocin ram was a good read for a noob planning on getting into overclocking
     
  7. doomtack

    doomtack New Member

    Rite (hoping that i'd understand by saying that).
    um... i'd like to do some o dis... BUT i too dumb for this...
    but th guide seems to explain alot.
     
  8. cereal_killer

    cereal_killer New Member

    does it make sense i try to oc a 512 mb kingstom value ram pc 2700 at 2.5, 3, 3, 7
    and 2 x 256mb corsair value ram pc 3200 with 3.0, 3, 3, 8 but when clocked to 166 mhz it runs at 2.5, 3, 3, 7
     
  9. mojo

    mojo New Member

    wouldn't hurt to try, but from my experience, value ram and value select gay when it comes to oc. I tried to oc value select PC 3200 2.5-3-3-8 with no success (I've tried 3 different 512MB sticks before).

    But you most likely have lifetime warranty on them so go ahead.
     
  10. mojo

    mojo New Member

    I modified my fsb:DRAM ratio and was able to get more MHZ on my memory. 257MHz DDR 514 @ 2-3-2-6 timings @ 3.2V.

    amazed myself. Tested overnight and work fine this morning. see screenshot below.
    [​IMG]
     
  11. Paradoxxx

    Paradoxxx New Member

    Just mentioning the chips on the Redline RAM takes a while to get broken in, after 1mth on vlads PC i was able to get atleast 10mhz more on an OC.

    Vlad = Value RAM with the same chips as redline.
     
  12. mojo

    mojo New Member

    I was thinking about going that route also, newegg had some Twinmoss PC 3200 with Winbond UTT on it, but apparently Twinmoss soon changed the RAM used on the memory. Is a gamble just like buying a 6800 not knowing whether it will unlock successfully or not.
     
  13. CRaZYMoFo

    CRaZYMoFo New Member

    CRUCIAL!!!!!!
    value ram iymc
    2x1gb sticks, great timings :)
     
  14. opium

    opium New Member

    ok am here to dust out the OCing stickies

    now i got some special info to help with those using Mushkin Redline

    yes Mushkin has some very good/bad ram in there pockets as they are infact making a lost with the ram

    because ppl are indeed damaging the ram, why?

    the ram need SPECIFIC BIOS SETTINGS AND TIMINGS

    now this might be too late or why de ass i should post this up but still take a read and if u do some what have the ram use the settings it will make yuh ram run better and even save the rma trouble

    now my ram is running with no probs and no more mem errors

    i suggest this for ppl who using tccd and bh-5 too who want high speeds with low timings
     
  15. CRaZYMoFo

    CRaZYMoFo New Member

    Will test the ballistix next week and let you know how they run.
    Mushkin redlines are rated @ 2-2-2-5 @ 250mhz @ 2.8v?
     
  16. mojo

    mojo New Member

    Mushkin Redline XP4000 512MB DIMMs are rated @ 3.3-3.5V 250MHz
    Best throughput is achieved @ 2-2-2-6(1T),2-2-2-7(1T)and 2-2-2-8(1T).
    For some strange reason, 2-2-2-5(1T) gives a slightly slower performance than the ones above.


    I have been using similar timings as what Opi mentioned on my rig, with some minor differences.

    tRC- 07. I noticed a little speed jump using tRC of 7 instead of 8.

    I also adjusted my chipset voltage to improve stability by your recommendation. However, my chipset Temperature jumped by 4 degrees Celcius. I am looking for a better chipset cooler since that is my highest temp right now.
     
  17. G_Pinkie

    G_Pinkie New Member

    From what i have seen trc 7 is the best for current amd cpus, a lil more bandwidth i believe it was.
     
  18. soldier

    soldier New Member

  19. phoenix31tt

    phoenix31tt New Member

    thats because ur ram is rated for 667 :S
     
  20. kriminal

    kriminal New Member

    teh hell no im not software tweaking my ram....my vid cards..hell yeh!!!
     

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