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How-to: Pencil mod your HD 3870!

Discussion in 'AMD / ATI' started by Random Murderer, Jan 2, 2008.

  1. asb2106

    asb2106 New Member

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    looking forward to seeing you thread!
     
  2. ace80

    ace80

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    Finally i'm back online.
    Got my new card a few days ago but had to wait to get mobo back from rma.
    His 3870 xt turbo @ stock 850/1190(2380)

    [​IMG]

    Here's the bios for all you who wanna look
     

    Attached Files:

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  3. Poulpy

    Poulpy New Member

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  4. Random Murderer

    Random Murderer The Anti-Midas

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    no, there's no capacitor there on my board, just open points.
    seems your manufacturer removed those points because they weren't doing anything.
     
  5. Poulpy

    Poulpy New Member

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    Arg.

    Maybe i am lucky.......is the one on the right the + or the ground ?

    If its the - , i am screwd as i dont know enought about vc design to find the the + for the vmem
     
  6. Random Murderer

    Random Murderer The Anti-Midas

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    The measure points are always +, you take the black lead of your DMM and ground it to your computer's chassis.
     
  7. thoughtdisorder

    thoughtdisorder New Member

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    I'm just curious....Why are the measure points always + ? Also, how did you figure that out?
     
  8. Random Murderer

    Random Murderer The Anti-Midas

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    The points are always + because you're measuring the amount of voltage being supplied to a specific component, not the return voltage.
    And I just kind of knew it already, simple electronics to those of us in-the-know. ;)
     
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  9. Poulpy

    Poulpy New Member

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    Think of it like electricity and electronics in a car:
    Your whole chassis is the - and a + is pulled from the ignition or the battery to the components, wich is why when you look for a + in a car, you attach the - tip of your DMM to a bolt for example and you use your + DMM tip to test cables until you find that gives the voltage you want.

    Same goes for the VCs apparently (i learned it today:p). Every set of components are fed on a common end with a - and then each gets the appropriate + voltage (1.3, 5.12, etc....).
    So to make it short, its your + that determines your voltage bot the -.

    Does it make sense or did i make it even more confusing ? I am asking because sometimes i understand perfectly things but cant explain them at all.:slap:

    ********************

    Mods follow up.
    Ok one 3870 moded and tested eventhough i scared myself by taking of a connection that i thought had been made by me with extra solder but no it wasnt:mad:. So i ended up spending 1hour to fix that by using a tiny strand of wire, pfff got real scared on this one.
    But the VC is working fine, i am at 1.46 on the gpu and 2.02 of the memory.
    Tomorrow i mod the second card and i will take pics along the process to make the thread i promessed.
    Btw here is a tip for those about to start too:

    When you want to check voltages, just hook the black (-) of your DMM to your case like this you can focus on manipulating the red tip of your dmm to quickly check vmem and vmgpu. Helped me to check voltages carefully and still be able to react fast if an emergency shutdwon was needed.(one hand on the psu switch and the other one with the red dmm tip to check voltages.


    More tommrow, i need to get some sleep, its 3:30am here :twitch:
     
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  10. thoughtdisorder

    thoughtdisorder New Member

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    Thanks RM & Poulpy! Makes sense.......:toast:
     
  11. ace80

    ace80

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    I just tried to overclock my 3870 but it hard locked at 860 from stock of 850, measured the voltage and its 1.33v at load. So do i need the bios fix or is it down to voltage?
    Also is the fixed bios provided by Random stock clocks of 775 or could i modify my own bios to get rid of the lock and keep 850?
     
  12. Random Murderer

    Random Murderer The Anti-Midas

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    Sounds like the PLL lock to me.
    There's a BIOS in the file I provided with the stock clocks of 860/1250. This may be your best bet.
     
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  13. ghost101

    ghost101 New Member

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    Random Murderer says thanks.
  14. Random Murderer

    Random Murderer The Anti-Midas

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    Ok, I included that program in the first post. Thanks for the heads-up.
     
  15. ace80

    ace80

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    Random, the two bios files that are included in the zip file have .sb extensions.
    I take it i just rename them?
    Also is it safe to flash in windows with winflash, i've always been told not to.
    Lastly are flashrom or atiflash compatible with these cards?
     
  16. trog100 New Member

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    i looked at your bios ace.. its version 075 but its only 61 k in size.. the ones without the 860 problem are all 64 k in size.. it seems u have the early one even thow the version is higher..

    i use winflash.. many times over.. but i recon u might get the sub system mismatch message.. error..

    your bio has many differences compared to the other ones.. similar to the gecube bios..

    odd they havnt gone for the bigger 64 k bios with such a late release card..

    the problem u have is the different none stock cooler requires different fan speeds setting and such..

    trog
     
  17. tigger

    tigger I'm the only one

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    I already posted the bios editor.
     
  18. Random Murderer

    Random Murderer The Anti-Midas

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    NO, do not rename them. .SB is a valid BIOS extension.
    I use the program included in the folder in my post. It is a Windows-based flashing program, and I have used it many times over on different systems without problems.:toast:
     
  19. trog100 New Member

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    the editor is also useful just for looking at a bios.. it reads the various voltages and speeds nicely.. for example aces ice turbo 3870 reads only 1.3 volts which does kinda surprize me.. they must be good chips..

    trog
     
  20. Dr. Spankenstein New Member

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    Just finished volt mod on one card this morn. Didn't have much time to dink with it. Set resistor to around 86k ohms and got 1.48v. Kicked in fan (Riva) to 80% temps were around 60C.

    Get ready for some shenanigans....
     
  21. asb2106

    asb2106 New Member

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    at that voltage you should hit some great core speeds! excited to see your results
     
  22. Dr. Spankenstein New Member

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    I'm excited too. Why does work ALWAYS get in the way of having fun? :(

    Gonna push this one HARD!
     
  23. Poulpy

    Poulpy New Member

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    Hey everyone

    Just letting you guys know that i havent forgotten about the thread i am supposed to make. Just havent had the time yet.
    Everything went cool, both GPUs are al the way to 1Ghz. On the other hand i find the mod for the memory to be useless as apparently those memory (on my cards at least) really dont like overclocking and evenless an increased voltage. Not a big deal if you ask me as VC mem overclock doesnt bring that much extra performance compared to a GPU overclock.
    So right now, stock speed on the memories but 1Ghz on the GPUs and 19000+ in 3DMark2006. Will post pics soon once i finish my last project which is a change in case to that one:
    [​IMG]
    http://www.newegg.com/Product/Product.aspx?Item=N82E16811133052
    This case is a giant, plenty of room for my watercooling and for that too:
    [​IMG] !!!!!!!

    More tomorrow when i get those 40Kg worth of packages :twitch:
     
  24. ace80

    ace80

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    Been having problems with my mobo not posting like some guys in other threads:mad:
    Anyway i've flashed the bios which has hopefully got rid of the 860mhz lock, my question to all before i begin oc'ing is whats the highest core clock you've achieved before pencil or hard modding?
     
  25. Dr. Spankenstein New Member

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    What's going on here!?! You folks are making me fear logging-in for catching this motherboard-killing disease! :eek:

    My attempts at pencil-mod got me 1.4V max which got me 879HMz top gaming stable speed and that was with stock cooler @ 100% fan speed. "The Haunted" got some wicked (do the kids still use that word?) voltage with this pencil-mod.

    It depends on the type/softness of the pencil lead, your technique and your PATIENCE!
     

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