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Under-performing Ram sticks

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  • Under-performing Ram sticks

    I've tested 2 different ram sticks (Team Group Xtreme 8GBx2 4133mhz 18-18-18-38, G.SKILL TridentZ RGB 8GBx2 3600mhz 18-22-22-42 for AMD) although both RAM modules are supposed to have a CAS latency of 18 Passmark is giving both sticks a latency of 30 I've attempted to overclock both sticks getting the T-force stick to 16-16-16-32 but still only displaying a memory latency of 30. My first thought was the bios might have needed an update so i went to MSI and downloaded the latest bios update for my motherboard (MSI x570-A PRO) and ran another test. I recieved the same results of latency's higher than rated. I even went through the pain of manually setting all the timings and sub timings. I still can not get a latency that is lower than 30. My best guess is the motherboard but it claims to be rated for up to speeds of 4400+(OC) and claims to have a DDR4 BOOST that is an "optimized circuit layout design that separates the memory transfer block to ensure the stability of the signal". My second thought was to check the QVL (Qulaified Vender List) to see if either ram sticks were on it and to my surprise neither stick was. However, a stick not being on a QVL has not always meant that compatibility wasn't possible just that is wasn't optimized automatically in the form of presets and profiles. I was wondering if anyone had any possible solutions before i go and bust out 300-400$ on an Asus x570 Maximus.

  • #2
    CAS latency of 18 Passmark is giving both sticks a latency of 30
    The number stamped on the sticks will never match benchmark numbers.
    CAS latency doesn't reflect the entire latency in getting data from the RAM into the CPU. Plus there is many many different measurement techniques, which can all give different answers. (e.g. reading a single byte vs reading a word, reading sequential bytes or random bytes, etc..)


    • #3
      How can i test for a potential bottleneck? I have tested almost 4 different sets of RAM modules and they give roughly the same result EVERY time with very different latency's different timings and different speeds. My assumption is still the motherboard. I have recently tested an expensive kit of G.SKILL 4400mhz with timings of 19-19-19-39 and i am still getting the same memory mark that I've been getting with the other 3 very different kits. Latency is still above 30 while although may not match CAS Its not even reaching passmarks own suggested averages. Every set of RAM modules ive tested have underperformed the average marks posted on passmark. This kit of G.SKILL that Ive just recently tested averaged almost 4000 Memory Mark yet i cant get it above 2900.


      • #4
        Years ago memory controllers were part of the motherboard. But now they are part of the CPUs.
        So some CPUs don't have a memory controller fast enough to take full advantage of the RAM speeds. Intel's CPUs have been better in this regard.
        If you are comparing your machine to others, make sure you take the CPU type into account and not just the RAM.

        But for many applications RAM latency doesn't have a big impact on the performance because the CPU's cache does such a good job in hiding the slower memory speeds.


        • #5
          Is there anything I should look for when trying to find RAM sticks that will score well on passmark. When I bought these G.Skill 4400 I was comparing the average score with the QVL of the motherboard. Or is it possible no matter the RAM I get it won't be able to be fully utilized by the CPU so waiting for the 4000 series and x670 would be a better option


          • #6
            There would be a cross over point. If you kept lower the speed of the RAM, eventually the CPU will be faster and the RAM would become the bottleneck.
            Also integrated graphics (GPUs) that share main RAM often do a better job of using the full bandwidth of the RAM. So depending on the GPU you are using, you might get some benefit from really fast RAM, even if the CPU can't use it.


            • #7
              Im currently using a GTX 1080 ASUS turbo. Its fairly old been holding out until either nvidia or AMD releases their new top of the line graphics cards. Ive entered the 99th percentile in every category except for RAM thats why ive been so deadset on improving it.