Is my RAM running at correct speed?


I just upgraded to Corsair Dominator GT 8GB DDR3-2133 CL9. 1.5V 9-11-10-27-2T

I went to BIOS, enabled X.M.P. Profile, and everything was automatically set to 2133 MHz, and 9-11-10-27-2T

It booted up perfectly fine, and I went to CPU-Z to check everything. Then I noticed at the Memory tab, that the DRAM Frequency said 1066.9 MHz instead of 2133 MHz. So I searched on Google "RAM running at half speed" and found that this is normal. Is that indeed normal? Because it's Dual Channel so it's 1066 MHz for each module, correct?

Ok, so then I went to the SPD tab. Selected slot #2, and it said at Max Bandwidth, it said: PC3-10700 (667 MHz). That doesn't seem normal to me! So my question is, which one is correct, the Memory tab or the SPD tab? Is my memory actually running at 2133 MHz?

My motherboard is Asus P8Z68-V PRO (B3) and CPU is i5 2500K @ 4.7 GHz 1.39V stable.

Thanks in advance,

2 answers Last reply
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  1. Both tabs are correct, and I believe you are getting the full speed out of your RAM.

    SPD = in short, are the instructions from the module to the motherboard on how to configure RAM access. For this question, you can likely ignore this tab.

    Memory = the more important tab for you and for this question. DRAM frequency is the number you're looking for. This number as reported by CPUZ needs to be x2 (e.g., 1066*2=2133). Not because of dual channel but because of DDR (Dual Data Rate).
    Keeping to the simplest of explanations, the modules are running at a raw 1066MHz, but due to DDR techniques, you are effectively getting 2133MHz.

    In simplest terms, your Corsair modules are running at the advertised 2133MHz. :)

    JEDEC standards explained in chart form
  2. Thanks homie, that was the answer I was looking for!
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