HD5870 Memory voltage

Discussion in 'Die-hard Overclocking & Case Modifications' started by Darkasantion, Feb 11, 2010.

  1. Darkasantion

    Darkasantion Master Guru

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    GPU:
    Club 3D HD5870 1035/1325
    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 ;). And I don't mind that.

    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(Radeon BIOS Editor) 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

    And yes I know the HD5870 isn't really bottlenecked by memory bandwith, but still I want to be able to push the entire card towards it's maximum, and that includes the memory aswell then :evil2:
     
  2. Enmity

    Enmity Maha Guru

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    GPU:
    EVGA 1080ti FE SLI
    my understanding is that you cant change the memory volts with these cards? and if so..how the hell would you keep it cool unless you have it watercooled? lol...

    With that said, it would be great to be able to clock the memory higher even though we know it provides a tiny increase..but hey we all like to see higher numbers in all of our hardware so i know what you mean...If anyone else has info on this, please, enlighten us :)
     
    Last edited: Feb 11, 2010
  3. Darkasantion

    Darkasantion Master Guru

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    GPU:
    Club 3D HD5870 1035/1325
    I will enlighten you, someone revealed the "secret" to me. The 2 voltages controlled by the BIOS, or the 2 options you can access with RBE are both related towards voltages inside the RV870 chip itself. One voltage(which you can also access with MSI Afterburner) is the voltage supplied to the "shader" domain of the chip, the part where the 1600 shader units are working.
    The other voltage you can access and modify is the voltage supplied towards the memory controller on the chip, not the memory itself. Increasing this might help a little when overclocking the memory, as you can push the voltage of the memory controller a bit higher, but those 8 chips keep running at 1.5V unless you start with a hard vmod :)
     

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