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Memory voltage with RBE.

Discussion in 'RBE' started by Darkasantion, Feb 11, 2010.

  1. Darkasantion New Member

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    Did a little searching on the voltage the memory on the HD5870 uses, to find "potential" headroom for overclocking, as the voltage might be lowered to safe power, but by raising it again you might create room for overclocking ;).

    Anyway, found out that the memory is made by Samsung, rated for 5000Mhz, and then needs 1.5Vmem. Also the room on the memory to play around with the voltages, without going beyond specifitations is ~0.045V.

    Specifactions are found here:Spec sheet
    You need to look at this specific part: K4G10325FE-HC04

    Why am I making this topic then? Well it's specified for 1.5V at 5000Mhz, yet according to RBE it "only" needs 1.15V(0.35V less!) to do 4800Mhz....
    I also did have a quick look at the ATI Overvolt tool for the HD5970, to check/confirm the memory readings and settings there with the RBE read outs, which should be right as AMD themselfs did release it (the tool is not provided anymore, and was removed by AMD's request). And these numbers do match, so the memory is really running on 1.15V

    So how come the memory can actually do 4800Mhz+ with 0.35V less than specified? Wrong read out, or cherry picked memory....? Last one would be cool, as this would mean that the memory has the potential to be raised from 1.15V towards 1.5V safely for higher clocks..... and we all want that don't we:D
  2. jaredpace

    jaredpace New Member

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    VDDCI reported in GPU-z is the voltage of the non-shader area of the core (vtt/uncore) of the gpu. VDDC is Core voltage. Both the VT1165's - the software programmable VRMs on the 5870 control voltages connected to the gpu. No software is controlling the voltage of those samsung memory IC's and they stay right around 1.5 +/- .05v. I thank Hipro5 for that insight. The reason ati's 5970 overvolt tool calls second ajdustable voltage memory is because you can still get a slight gain in memory speed from VDDCI.

    You may receive a small boost in the overclockablity of the memory because the gpu's memory controller residing in the uncore receiving boost from increased VDDCI. Result i assume is a more stable transfer of data.

    Memory IC's will always run at the spec'd voltage unless you are hard modding them directly. For that you gotta break out the soldering iron - which i don't have any experince with.

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