How to remove Fermi and Kepler laser cuts to fully enable core. 680m success

Discussion in 'Hardware Components and Aftermarket Upgrades' started by Khenglish, Jul 24, 2020.

  1. Khenglish

    Khenglish Notebook Deity

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    Oh yes it would make sense that the memory controller for the missing memory turns on. Do you have a bunch of green lines horizontally across the screen? If so then that's what's happening.
     
  2. poprostujakub

    poprostujakub Notebook Consultant

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    It looks like that, different pattern after each power up, sometimes with erratic flashes. Pattern also changes after pressing power button, when laptop is turned on.
     

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  3. Khenglish

    Khenglish Notebook Deity

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    Ok I don't know what that is. Missing memory would give you a 75% correct image.
     
  4. TheQuentincc

    TheQuentincc Notebook Evangelist

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    not really, sometime a gpu refuse to boot/display something with only one bad memory chip.
    Your experience goes along my theory that it's a "debug" thing that fully enable the core, AFAIK bios does not unlock the core, a guy upgraded the core of his 1060 mxm to a 1070 + two more memory chip and it worked with the 1060 bios.
     
  5. Khenglish

    Khenglish Notebook Deity

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    I've gotten that with AMD GPUs but not Nvidia, but maybe an address solder issue fully breaks it. With 1/4th of chips missing you'll get an image where 3/4th of the lines on the screen are normal and the others are a solid or wrong color. The BIOS POST doesn't even have Nvidia GPU memory initialized. There was someone with a 780 who removed all memory chips and it would still display POST artifact free.
     
  6. ssj92

    ssj92 Neutron Star

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    I have k4000m as well, guess wouldn't be worth destroying if @TheQuentincc didn't get theirs working.

    So how are you guys exposing those points, sanding the green layer around core?
     
  7. TheQuentincc

    TheQuentincc Notebook Evangelist

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    sanding paper yes, P800 for me, cut to a small piece that I hold at the end of a cotton swabs and a bit of isopropyl alcohol, that's making a clean area and does not destroy the core.
    Then for soldering I was having trouble with the 760 (my K4000M was so f*** lucky) so I used kapton tape all around the area, put flux on the area, a tiny bit of solder on the end of my iron, then solder those two pads, after that I checked the resistance between this to ground and it was 277k (if it's 0 that's bad, it should be 10+k) :)

    edit : for now we don't know if this is unlocking a 1344 cuda/256b memory card to a 1536 cuda/256b memory only or not
     
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  8. ssj92

    ssj92 Neutron Star

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    @Khenglish @TheQuentincc Do either of you know how to modify nVidia vBIOS? I want to remove the UEFI (gop) portion of vBIOS from 9 series/Maxwell quadro based cards to test in older laptop.

    I read something about header needs to be fixed or something? I am trying to learn vBIOS editing but it seems way beyond my comprehension to modify like that.
     
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  9. Khenglish

    Khenglish Notebook Deity

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    @ssj92 Nope, idk how to do that kind of mod.

    After unlocking the 680m I did a lot of mods:

    Without mods other than unlock, card was stable at stock voltage at 967 core 4700 ram. Kepler series cards clock the core in 13 MHz increments, with higher values always rounding down.

    1. Switched out all 330µF caps for 470µF caps. Added missing 22µF ceramic cap for core. Switched 1µH memory inductor for .56µH inductor. Added 3 missing 2.2µF 19V caps.
    Result: core stability increased to 980, memory to 5 GHz.

    2. Added 60µF of ceramic caps directly under core. This helps Maxwell cards a lot.
    Result: Only made 993 MHz less unstable.

    3. Increased ram voltage to 1.51V.
    Result:Ram stable clocks increased to 5400 MHz.

    4. Added 7 missing 1µF RAM caps found on 780m and 880m, and 30 missing caps only found on the 980m. Piggy backed additional 470µF cap on ram caps. Added 2x 47µF 19V caps. 980m needs these to not lose ram overclock when core is overvolted. 680m has better 19V filtering though.
    Result: No RAM clock improvement. :(

    5. Piggy backed 7x 330µF caps on the 470µF core caps.
    Result: Core stability increased to 993 MHz. 1006 MHz almost stable. When at 1.05V stability increased more from 1059 to 1085.

    6. Reduced RAM voltage to 1.41V. Ram overvolt mostly just wasted power and card thermal throttles when running 4K at stock core voltage. Kepler is incredibly hot compared to Maxwell.
    Result: RAM stable at 5175 MHz.

    7. Added additional 70µF of ceramic caps directly under core.
    Result: Core now stable at stock voltage at 1006 MHz.

    Voltage filtering mods increased core clocks from 967 to 1006 MHz. 4% more speed for free. The only other mods I know of that work are adding wires to increase power efficiency between the core and inductors, but these mods are uuuuugglllyyy, are hard to do, and make the card more annoying to install. I consider mods done unless I want to replace the memory. I did find an ebay seller for 7GHz rated chips for $50 that doesn't appear to be a chip relabeling scam... Kepler IMC tops out around 7.5 GHz. idk if there is another issue other than ram quality which results in the low RAM clocks. Typically you expect 6GHz at 1.5V on older chips like these. Poor voltage scaling is a sign of poor ram chips. 980m boards run 6 and 7 GHz rated samsung chips at 1.35V both around 6GHz, but the 7GHz rated chips clock much higher at 1.5V.

    frontside_done_small.jpg
    backside_done_small.jpg
     
    Last edited: Jul 31, 2020
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  10. TheQuentincc

    TheQuentincc Notebook Evangelist

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    You tempt me to buy a 680M and Epower it while watercooling it :eek:
    Indeed Kepler card can consume a lot of power and be very hot, I barely manage to cool my 770 on watercooling while the vcore is at 1.45v and around 1450MHz, it consume about 450w in Firestrike GT1, thanksfully (but sadly too) I hit the OVP or the OCP on my card :/, I also believe it's core is pretty weak, it does 1350MHz at stock 1.21v but does not scale really well :(
    Did you ever tried to mix memory chip ? like keeping the same brand but use 6 and 7GHz chip ? might need same chip revision ?
    I think I read somewhere that kepler IMC is powered by the memory power phase, so increasing voltage should result in better clocks if everything is well cooled.
     
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