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Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

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  • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

    Hi Lsdmeasap,

    Thanks for all the wonderful info here: When I recently bought a new PC, it helped me immensely in understanding all about the RAM technology I now had. I googled and researched a lot, and there are a couple of things that might be of interest (or at least my noobishness might entertain!)

    1) You write:
    tRAS = tCL + tRCD + tRP (+/- 1) so that it gives everything enough time before closing the bank.
    ... Everybody else says that also, but I don't think that's right!

    A DDR2 spec says:
    Once a bank has been activated it must be precharged before another Bank Activate command can be applied to the same bank. The bank active and precharge times are defined as tRAS and tRP, respectively. The minimum time interval between successive Bank Activate commands to the same bank is determined by the RAS cycle time of the device (tRC).
    ... a diagram in that PDF shows "RAS Cycle Time = Bank Active time + Bank Precharge time": i.e. Bank Active is followed by Precharge.
    (It also shows: "RAS Cycle Time >= tRC, Bank Active >= tRAS, Bank Precharge time >= tRP".)

    If Bank Active time preceeds and does not include Precharge, how can tRAS = tCL + tRCD + tRP (+/- 1)?

    I suspect actually that, tRAS = tCL + tRCD + tXXX, where tXXX is some unspecified internal chip operation minimum time, and that tXXX just happens to be have the same numerical value as tRP (+/- 1), in the same way that tCL, tRCD & tRP just happen to often have the same numerical value.

    2) Isn't tRD a little mysterious?

    I googled high and wide and even download a few Intel MCH spec docs, and tRD is not documented for recent DDR2 MCH chips!
    It is surely an MCH configuration value, but not documented. I did find a forum post by the author of the memset program where he and others were discussing which MCH register it was in.

    As near as I can tell, tRD is more or less the equivalent to tCL, but on the CPU/MCH side of the bus, rather than on the MCH/Memory side of the bus.
    (tCL is the clock delay - memory clock - between the MCH giving a read command (CAS) to the memory and data becoming available, whereas tRD is the clock delay - CPU FSB clock - between the CPU giving a read command to the MCH and data becoming available.)

    Given that tCL is just about the most important memory parameter, and the one of the first things that people tweak, it's surprising that many 'how to tweak memory speed' articles don't even mention tRD.
    The AnandTech: ASUS ROG Rampage Formula: Why we were wrong about the Intel X48 link on the first page of this thread is about the only place I found that talked about it in depth. They have a formula which can more-or-less be arranged into:

    tRD > (tCL + x) * FSB / DRAM_Freq

    ...where 'x' is a funny parameter not explained well.

    I'd like to think x is tCCD (usually =2?), because that would make sense given the process. Or perhaps the formula is:

    tRD > (tCL / DRAM_Freq + x) * FSB

    ... where x = 5/1000 (5ns, plucked out of the air...)

    Comment


    • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

      Well tRAS is a "Usually" type of thing, sometimes it can differ. You can see the same noted here by the maker of Memset
      Tweakers.fr

      tRD, ya it can be mysterious at times, it's new tech so ya never know what to expect.

      From the above linked site
      -Performance Level / Read Delay (tRD).
      tRD is the number of memory clocks from DRAM Chip Select# assert
      to Host Data Ready# assertion on the FSB.
      Hight influence on performance and stability.

      Comment


      • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

        hi all, i got a problem setting the patriot 2x2gb ddr3 llk kit, it's not working in dual channel mode on my ma790xt-ud4p. i already post the details here :
        http://forums.tweaktown.com/f69/ga-m...1333llk-35690/
        pls help
        AMD Phenom II X4 955 BE 3.2Ghz
        Gigabyte GA-MA790XT-UD4P rev 1.0 F7
        Sapphire Vapor-X HD4870 1GB DDR5
        OCZ Gold AMD LV 4GB kit 9-9-9-20 1333Mhz (OCZ3G1333LVAM4GK)
        Seagate Barracuda 500GB 7200.12 SATA
        CoolerMaster RC690 BLACK PURE (stock fans) + Clear Side Window
        FSP Epsilon 85PLUS 600 watt
        AVR Matsunaga 1000N
        Xigmatek HDT-s1283 Red Scorpion
        Windows 7 Ultimate 64 bit
        Pioneer DVR-S18L 22x22 SATA
        Samsung SyncMaster 733NW
        2+1 Altec Lansing AVS300

        Comment


        • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

          inforcer can you try another cpu? That 955BE has the dual channel memory controller on it. You may have a defective memory controller.
          AMD Phenom II X4 955 Black Edition Processor Introduction :: TweakTown
          http://forums.tweaktown.com/gigabyte...ench-test.html
          http://www.gigabyte-usa.com/FileList...ios_qflash.pdf
          Phenom II 945 @ 3.2Ghz w/Thermaltake Big Typhoon Pro 14 CPU Cooler
          Gigabyte GA-MA78GM-S2H rev.1.1 F11
          Sapphire 3870HD / 100225L / 512MB / ddr4
          4GB / Kingston / KHX8500D2K2/2GN / 5-5-5-18 / 1066Mhz
          (2) WD Caviar / WD2500AAKS/ 250GB in SATA RAID-0
          (1) WD Caviar / WD2500AAKS/ 250GB in SATA AHCI
          (2) IDE's 1 8XdualDVDRW 1 52x32x52x CDRW
          Antec /Neo HE550 / 550W
          Mid size ATX case with show through panel
          2) 80x80 front fans (1) 120x120 rear fan and small nb fan
          Microsoft comfort curve USB keyboard 2000 ver.1.0
          Logitech G500 USB mouse
          Monitor: CMV937A
          7.1+2 Channel High Definition ALC889A
          Dual boot Windows 7 32bit home & Windows 7 64bit home

          Comment


          • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

            inforcer there is a later bios to flash to scroll down on this url.---->
            GIGABYTE - Support&Download - Motherboard - BIOS - GA-MA790XT-UD4P (rev. 1.0)
            http://forums.tweaktown.com/gigabyte...ench-test.html
            http://www.gigabyte-usa.com/FileList...ios_qflash.pdf
            Phenom II 945 @ 3.2Ghz w/Thermaltake Big Typhoon Pro 14 CPU Cooler
            Gigabyte GA-MA78GM-S2H rev.1.1 F11
            Sapphire 3870HD / 100225L / 512MB / ddr4
            4GB / Kingston / KHX8500D2K2/2GN / 5-5-5-18 / 1066Mhz
            (2) WD Caviar / WD2500AAKS/ 250GB in SATA RAID-0
            (1) WD Caviar / WD2500AAKS/ 250GB in SATA AHCI
            (2) IDE's 1 8XdualDVDRW 1 52x32x52x CDRW
            Antec /Neo HE550 / 550W
            Mid size ATX case with show through panel
            2) 80x80 front fans (1) 120x120 rear fan and small nb fan
            Microsoft comfort curve USB keyboard 2000 ver.1.0
            Logitech G500 USB mouse
            Monitor: CMV937A
            7.1+2 Channel High Definition ALC889A
            Dual boot Windows 7 32bit home & Windows 7 64bit home

            Comment


            • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

              Originally posted by artdrivers View Post
              inforcer can you try another cpu? That 955BE has the dual channel memory controller on it. You may have a defective memory controller.
              AMD Phenom II X4 955 Black Edition Processor Introduction :: TweakTown
              that's what i'm afraid of...


              Originally posted by artdrivers View Post
              inforcer there is a later bios to flash to scroll down on this url.---->
              GIGABYTE - Support&Download - Motherboard - BIOS - GA-MA790XT-UD4P (rev. 1.0)
              the stock bios wont detect the 955BE correctly.
              then i flash the bios to the latest F5, problem solved, now windows 7 ultimate 64 can detect the 955BE correctly.

              i notice the description said :
              F6 (2009/09/16) Update CPU ID (Support AGESA 3.5.3.1 code / AM3 C3 CPU)
              F5 (2009/08/06) Update CPU ID(AGESA 3.5.3.0 for PhenomII /AthlonII AM3 CPU)

              Warning:
              Because BIOS flashing is potentially risky, if you do not encounter problems using the current version of BIOS, it is recommended that you not flash the BIOS. To flash the BIOS, do it with caution. Inadequate BIOS flashing may result in system malfunction.
              so... does that mean, i should stick with F5 and try to find the timings/settings for the 2x2GB kit, or flash to the latest F6 ?
              AMD Phenom II X4 955 BE 3.2Ghz
              Gigabyte GA-MA790XT-UD4P rev 1.0 F7
              Sapphire Vapor-X HD4870 1GB DDR5
              OCZ Gold AMD LV 4GB kit 9-9-9-20 1333Mhz (OCZ3G1333LVAM4GK)
              Seagate Barracuda 500GB 7200.12 SATA
              CoolerMaster RC690 BLACK PURE (stock fans) + Clear Side Window
              FSP Epsilon 85PLUS 600 watt
              AVR Matsunaga 1000N
              Xigmatek HDT-s1283 Red Scorpion
              Windows 7 Ultimate 64 bit
              Pioneer DVR-S18L 22x22 SATA
              Samsung SyncMaster 733NW
              2+1 Altec Lansing AVS300

              Comment


              • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                i should stick with F5 and try to find the timings/settings for the 2x2GB kit, or flash to the latest F6 ?
                I would flash to the latest bios using the QFLASH utility your board came with. Be sure to set your bios to Load optimized defaults first though. Here is a great tutorial for Flashing a bios on all the latest Gigabyte boards. http://forums.tweaktown.com/f69/bios...h-guide-27576/
                Last edited by artdrivers; 10-24-2009, 09:29 PM.
                http://forums.tweaktown.com/gigabyte...ench-test.html
                http://www.gigabyte-usa.com/FileList...ios_qflash.pdf
                Phenom II 945 @ 3.2Ghz w/Thermaltake Big Typhoon Pro 14 CPU Cooler
                Gigabyte GA-MA78GM-S2H rev.1.1 F11
                Sapphire 3870HD / 100225L / 512MB / ddr4
                4GB / Kingston / KHX8500D2K2/2GN / 5-5-5-18 / 1066Mhz
                (2) WD Caviar / WD2500AAKS/ 250GB in SATA RAID-0
                (1) WD Caviar / WD2500AAKS/ 250GB in SATA AHCI
                (2) IDE's 1 8XdualDVDRW 1 52x32x52x CDRW
                Antec /Neo HE550 / 550W
                Mid size ATX case with show through panel
                2) 80x80 front fans (1) 120x120 rear fan and small nb fan
                Microsoft comfort curve USB keyboard 2000 ver.1.0
                Logitech G500 USB mouse
                Monitor: CMV937A
                7.1+2 Channel High Definition ALC889A
                Dual boot Windows 7 32bit home & Windows 7 64bit home

                Comment


                • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                  If F5 supports a CPU, F6 also would support the same CPU

                  Comment


                  • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                    Originally posted by Lsdmeasap View Post
                    If F5 supports a CPU, F6 also would support the same CPU
                    thx for the info, i'll flash it asap *cross fingers*
                    AMD Phenom II X4 955 BE 3.2Ghz
                    Gigabyte GA-MA790XT-UD4P rev 1.0 F7
                    Sapphire Vapor-X HD4870 1GB DDR5
                    OCZ Gold AMD LV 4GB kit 9-9-9-20 1333Mhz (OCZ3G1333LVAM4GK)
                    Seagate Barracuda 500GB 7200.12 SATA
                    CoolerMaster RC690 BLACK PURE (stock fans) + Clear Side Window
                    FSP Epsilon 85PLUS 600 watt
                    AVR Matsunaga 1000N
                    Xigmatek HDT-s1283 Red Scorpion
                    Windows 7 Ultimate 64 bit
                    Pioneer DVR-S18L 22x22 SATA
                    Samsung SyncMaster 733NW
                    2+1 Altec Lansing AVS300

                    Comment


                    • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                      Memset problem or not ?



                      APPLY button is greyed and i can't apply any changes

                      -but, if I set System Memory Multiplier, in BIOS to AUTO, then I can use APPLY button in windows

                      question is why?
                      help please !

                      bios is F12 (should I update to F13)?
                      OC--> FSB=445, FSB:RAM=1:1



                      PS. sorry for bad english
                      MBO:EP45-DQ6, CPU:Q9650 @ 4,00 GHz, Cooler:IFX-14 + 2x120 mm, RAM:OCZ PC2-8500 Reaper HPC 2x2 GB
                      HDD:2 x WD 640 AAKS, GPU:Sapphire HD4870 + scythe musashi, PSU:Corsair VX450, MON:Asus VW221D

                      Comment


                      • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                        Try settings Static tRead Value manually for both channels, see if this changes it.

                        Comment


                        • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                          Originally posted by E-mil View Post
                          Memset problem or not ?
                          Post this direct to Felix here

                          Comment


                          • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                            Originally posted by Chike View Post
                            Try settings Static tRead Value manually for both channels, see if this changes it.
                            I'll try tonight

                            thx

                            Originally posted by stasio View Post
                            Post this direct to Felix here
                            I saw that thread already, but..
                            I registered last week (second time) but my acount is not activated yet

                            thanks anyway
                            (hvala)
                            Last edited by E-mil; 11-18-2009, 07:44 AM.
                            MBO:EP45-DQ6, CPU:Q9650 @ 4,00 GHz, Cooler:IFX-14 + 2x120 mm, RAM:OCZ PC2-8500 Reaper HPC 2x2 GB
                            HDD:2 x WD 640 AAKS, GPU:Sapphire HD4870 + scythe musashi, PSU:Corsair VX450, MON:Asus VW221D

                            Comment


                            • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                              Originally posted by Chike View Post
                              Try settings Static tRead Value manually for both channels, see if this changes it.
                              yes, now i can change memory timings

                              thanks

                              can you explain why
                              MBO:EP45-DQ6, CPU:Q9650 @ 4,00 GHz, Cooler:IFX-14 + 2x120 mm, RAM:OCZ PC2-8500 Reaper HPC 2x2 GB
                              HDD:2 x WD 640 AAKS, GPU:Sapphire HD4870 + scythe musashi, PSU:Corsair VX450, MON:Asus VW221D

                              Comment


                              • Re: Memory Timings Explained W/ Suggested Timings & Memset VS. BIOS

                                Originally posted by E-mil View Post
                                yes, now i can change memory timings

                                thanks

                                can you explain why
                                It was disabled in MemSet (Performance Enhance was blank) so it may be just a software bug that can be fixed, or it may be impossible for it to change it.

                                Try reporting the author of MemSet, if it's only a bug he may want to fix it.

                                Comment

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