780m with GTX 780 core?

Discussion in 'Hardware Components and Aftermarket Upgrades' started by TheReciever, Jul 8, 2018.

  1. TheReciever

    TheReciever D! For Dragon!

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    Im only citing @Khenglish experiment that he shared on Tech | Inferno a while back with his 980m w/ GTX 980 core modification as my reference for this scenario.

    Just wondering what the plausibility is for this. I have a dead 780m here and was wondering if its worth holding onto for a project down the line.

    I dont know much of what is needed for this to work. Im guessing the memory interface may be a problem? The GTX 780 uses a 384-bit bus and the 780m uses a 256-bit bus.
     
    Last edited: Jul 8, 2018
  2. Mobius 1

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    780m is gk104, while 780 is gk110

    different pinout I would assume
     
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  3. TheReciever

    TheReciever D! For Dragon!

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    Ah right of course, then maybe the GTX 680?

    Though I assume some of the gains between 780m and the GTX 680 would be the memory speed.

    GTX 770 might pull just a bit more, iirc its a refreshed GTX 680
     
  4. Mobius 1

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    isn't the 780m already a full 680 core?
     
  5. TheReciever

    TheReciever D! For Dragon!

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    Yeah pretty sure thats the case.

    Just wondering if there is anything I can do with the dead 780m instead of just selling it on ebay to be honest.

    I dont know if I can repair the 780m just on what I have on hand.
     
  6. Khenglish

    Khenglish Notebook Evangelist

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    780 core cannot work. The GK110 core is far larger than GK104.

    You can use a maxwell GM204 core though. Good luck with the bios mod to make that work.
     
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  7. TheReciever

    TheReciever D! For Dragon!

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    I think someone is trying that with their Alienware 14, from 765m to 965m.

    Well it was just a thought, thanks for chiming in everyone.

    The sound began to distort and mouse was lagging before it failed to initialize upon reboot. No artifacts of any kind before it failed. 56c load temp for the majority of its life when I had it (bought this laptop used) and had stock vBIOS before I flashed the modded slv7 vBIOS a day or two after purchase. Ran stock clocks.

    Any ideas of how to repair? I've tried baking it twice.

    Once at 385F for 8 minutes which worked and 2 days later at 400F for 10 minutes which didnt revive the card.

    There is a bit of browning around the R22 gray boxes and the smaller unlabeled one. I dont think they are bad as they arent malformed at all but maybe that browning is dirtying the power being delivered rendering the card inert?
     
  8. Danishblunt

    Danishblunt Notebook Virtuoso

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    wait what? The GM204 core would be plug and play on the 780M PCB?

    @TheReciever You do not bake a card for 10minutes on 400F. Fixing the GPU Bumps is already going to happen at far less temps such as 260F. Any higher temps (above 180c or ~360F) can detach or harm (longer periods of time on high heat) componennts.

    If you're not into electrinics I'd recommend selling the card since you might have damaged it to a point where you can't really fix it.
     
    Last edited: Jul 8, 2018
  9. TheReciever

    TheReciever D! For Dragon!

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    Revived my 1000m 3 times with same methodology and several 6850/6870 cards.

    Card was dead to begin with so not losing sleep over it.
     
  10. Khenglish

    Khenglish Notebook Evangelist

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    Yes, GK104 and GM204 share the same bga and the cores can be interchanged. A 780m vbios will never be able to run a GM204 core though.

    If you're going to fix a card you need to heat it over the melting point of solder, which is 217C. Heating to less than this may temporarily improve a card since high heat tends to straighten cards out, bringing broken solder connections back into contact, but the improvement will not be permanent unless the solder is melted. You also should get solder flux around the bga, as this will improve how well the connections resolder.

    Make sure the card is on a flat surface as all solder on the card will be molten. Also make sure all stickers are removed as they can pull components off as they heat and curl. If the card has not been used in over a month you need to bake the moisture out of it first, or else it will literally pop like popcorn. Hold 100C for 5 hours to bake out moisture.

    The card will permanently discolor. Discoloration starts with anything over around 130C, and happens more quickly the hotter you go. This is mostly cosmetic. The card does weaken, but this only matters if you want to go for a full reball where you run a desoldering braid over the bga.
     
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