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

    Reputations:
    728
    Messages:
    1,005
    Likes Received:
    876
    Trophy Points:
    131
    I picked up a 680m for a backup card and to test out my theory on how to find and disable laser cuts. The operation was a success and now the card's core is now fully enabled and artifact free. vBIOS mods were unnecessary, but SVL7 modded vbios was used for extended overclocking limits. This mod method should work on any Fermi or Kepler card, but not later, as later cards do not have laser cuts.

    super_680m.png

    The laser cuts are on the core packaging, not the core. They are not visible with the top coating present. Below is an image of my original deceased 680m with the top coating and capacitors removed. The laser cut which disables 1/8th of the core is boxed in green. Both sides need to be reconnected.

    noskin.jpg

    While I removed all of the coating, you just need to expose the green box. Even on the working card I exposed far more copper than necessary, as I didn't know which laser cuts mattered. You can see a cluster of 5 cuts to the upper left of the green box. Reconnecting these did nothing that I could observe. Maybe they are related to quadro features.

    I pried off the steel chip guard around the core with a strait edge razor and heat gun. This is not necessary as the cut is very close to the core. You just need to peel off the plastic covering. Desktop cards will have a big IHS though, which will need to be removed.

    I recommending wrapping sandpaper around a screwdriver to remove the insulator as shown.

    sanding_better2.jpg

    Below is the laser cut exposed on the working card.

    laser_before2.jpg
    You can see I have solder on the card for where I tried bridging the cluster of 5 cuts. This was pointless. The 680m has an open memory cap pad just to the left of the core disabling laser cut. I may fill this cap in at some point. The cap I knocked off when removing the chip guard was on the opposite corner.

    laser_after2.jpg

    There is a tiny dab of solder bridging the laser cut. This took many tries. Typically I soldered the laser cut to the surrounding ground plane.

    I haven't voltmodded the card yet, but I did upgrade capacitors and the memory inductor. I did run 3dm11 and took the #1 hwbot spot at 980 MHz despite @Johnksss somehow clocking his card up to 1130 MHz. I'd be lucky for 1080 MHz at 1.05V even with the cap mods which added about 20 MHz to core clocks.

    https://hwbot.org/submission/4506549_khenglish_3dmark11___performance_geforce_gtx_680m_9536_marks

    I wish to thank whoever made the old mobility 9800 core unlock guide many many years ago. This is basically the same concept.
     
    Last edited: Jul 24, 2020
  2. Raidriar

    Raidriar ლ(ಠ益ಠლ)

    Reputations:
    1,565
    Messages:
    5,609
    Likes Received:
    4,045
    Trophy Points:
    431
    Incredible work!
     
    Vasudev, Papusan, ssj92 and 3 others like this.
  3. Khenglish

    Khenglish Notebook Deity

    Reputations:
    728
    Messages:
    1,005
    Likes Received:
    876
    Trophy Points:
    131
    Thanks! If only I did this 8 years ago.
     
    Vasudev, Mr. Fox, joluke and 5 others like this.
  4. Johnksss

    Johnksss .

    Reputations:
    11,319
    Messages:
    19,192
    Likes Received:
    11,906
    Trophy Points:
    931
    If only I had this mod back then. :)

    Great Job!
     
    Vasudev, Mr. Fox, DavyGT and 3 others like this.
  5. Khenglish

    Khenglish Notebook Deity

    Reputations:
    728
    Messages:
    1,005
    Likes Received:
    876
    Trophy Points:
    131
    This would have been a great mod for when the 480 and 780 ti were the top cards. Easier to win at LN2 benches when your core is bigger than everyone else's.
     
    Papusan, jc_denton and Johnksss like this.
  6. Johnksss

    Johnksss .

    Reputations:
    11,319
    Messages:
    19,192
    Likes Received:
    11,906
    Trophy Points:
    931
    Very true!
     
    Vasudev and jc_denton like this.
  7. jc_denton

    jc_denton BGA? What a shame.

    Reputations:
    8,987
    Messages:
    2,662
    Likes Received:
    4,996
    Trophy Points:
    281
    Very cool stuff!
     
  8. Khenglish

    Khenglish Notebook Deity

    Reputations:
    728
    Messages:
    1,005
    Likes Received:
    876
    Trophy Points:
    131
    I added the 1 knocked off and 1 never installed memory caps on the core and reskinned it.

    reskinned.jpg

    I am out of liquid metal (I thought I had a full spare tube...), which may be affecting clocks since the corners aren't properly covered. Overvolting memory from 1.35V to 1.52V only increased memory clocks from 5ghz to 5.4ghz, so memory overclocking on the 680m is still junk despite it having the same RAM chips, voltage, and buck converter setup as the 780m. With 1.35V good for 5ghz, 1.5V should be good for 5.6 to 6, so something is weird on the 680m.

    https://www.3dmark.com/3dm11/13968623

    Slight score improvement, but in no way worth the power. I'm going to dial the overvolt back to 1.4V after getting some overvolted core runs with added external cooling.
     
    Vasudev and Papusan like this.
  9. moral hazard

    moral hazard Notebook Nobel Laureate

    Reputations:
    2,769
    Messages:
    7,950
    Likes Received:
    78
    Trophy Points:
    216
    Awesome thread!
    Wish this technique worked for newer GPUs or even CPUs.

    Does anyone have a link to the old guide? Sounds like a fun read.
     
  10. Khenglish

    Khenglish Notebook Deity

    Reputations:
    728
    Messages:
    1,005
    Likes Received:
    876
    Trophy Points:
    131
    It may have been on the Dell community forums, which don't keep threads around very long. The mobility radeon 9800 could have its core config unlocked from 8/4 pixel/vertex pipes to 16/6, which was an enormous improvement. The laser cuts were much bigger and visible through the top insulator, so the mod is the same idea, just a bit easier. The magnifying glass I took a picture through is 10x magnification so after the 9800 the laser cuts got way smaller.
     
    Vasudev likes this.
Loading...

Share This Page