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Rules for primary, secondary and tertiary Timings

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  • Rules for primary, secondary and tertiary Timings

    Hi,

    i tried to find here some explanation or documents which help me understanding the "rules" or "basics" for the timings of DDR4 RAM especially B-Die G.Skill.
    What i found out until now is the following:

    primary Timings

    tCL = ...
    tRCD = ...
    tRP = tRCD
    tRAS = tRCD*2 or tRCD+tCL
    CR = 2



    secondary Timings

    tWR = 10 bis 16
    tRFC = 10 * tRAS
    tRRD_S = 4 to 6
    tRRD_L = tRRD_S or tRRD_S +2
    tWTR_S = auto (depends on tWRRD_sg & dg)
    tWTR_L = auto (depends on tWRRD_sg & dg)
    tRTP = tWR / 2 (is not working for me, i use little bit below tWR)
    tFAW = tRRD_S * 4
    tCWL = tRCD - 3



    tertiary Timings

    tREFI = 65535 Spec says 7.8*(4133/2)=16119

    tCKE = 4 to 8

    tRDRD_sg = 6
    tRDRD_dg = 4
    (important for reading bandwith)
    tRDRD_dr = only needed for dual ranked DIMMs
    tRDRD_dd = 6


    tWRWR_sg = 6
    tWRWR_dg = 4
    (important for writing bandwith)
    tWRWR_dr = only needed for dual ranked DIMMs
    tWRWR_dd = 6


    tRDWR_sg = 12 to 15
    tRDWR_dg = 12 to 15
    tRDWR_dr = only needed for dual ranked DIMMs
    tRDWR_dd = 13 to 16 ( tRDWR_dg + 1)
    (tRDWR some say it is important for AVX commandos, if you go lower it can heat the up the CPU more and more)

    tWRRD_sg = 29 to 32 ( tWRRD_dg + 5)
    tWRRD_dg = 24 to 27 ( tWTR_S +20 )
    tWRRD_dr = only needed for dual ranked DIMMs

    tWRRD_dd = 4 to 6 (tWRRD some say if you go too low you can reset/delete your BIOS)


    IOL, RTL i let them on auto



    So please can someone say something about the timings, about "rules" or if you have links to documents which help understanding i would be glad.

    Thx in advance

    hq
    timings test
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