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GeForce 8800 GS/GT/GTS Voltmods

Discussion in 'Articles' started by largon, Feb 28, 2008.

  1. quadomatic New Member

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    Thanks for linking me to this thread Largon.

    I bought the eVGA 9600GSO Dual Slot edition ($47 on newegg right now!!!), and so I'm going to go ahead and try this mod. Is it worth doing even if I'll be using the default dual slot cooler? Also, what variable resistors should I buy? I found these on radioshack (I could order from mouser, but with shipping it would be cheaper just to get them from radioshack)?

    Errr...I'm guessing I'd need to order them on mouser.com or something. Radioshack doesn't carry resistors of the proper resistance for this.

    Here are some resistors, would these work?

    500 ohm potentiometer for GPU volt mod
    http://www.mouser.com/Search/ProductDetail.aspx?qs=/zPWuUUsT7MBOUWHGrcugA==

    20 Kohm potentiometer for memory volt mod
    http://www.mouser.com/Search/ProductDetail.aspx?qs=m0BA540hBPd%2bnXSkPPJiaQ==

    50 Kohm potentiometer for reverse voltage memory mod
    http://www.mouser.com/Search/ProductDetail.aspx?qs=2jxZDUMdHjixhK9QkzGa9g==

    4.7 Kohm potentiometer for OCP:
    http://www.mouser.com/Search/ProductDetail.aspx?qs=3eDEvvxjZ0B2E6V7iiNcag==

    OR (wasn't sure which to go with)

    2.0 Kohm potentiometer for OCP:
    http://www.mouser.com/Search/ProductDetail.aspx?qs=yLGXVRudD3ptg/FCghk3hw==

    Thanks
     
    Last edited: Sep 15, 2008
  2. jeanpieterse New Member

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    Hi Largon,

    Tell me, In stead of using this mod what do u think about using NiBiTor..? Because u can also change your voltage on NiBiTor.. Someone said that it does't work.. But why does my frame rate change when i adust the voltage in my bios with NiBitor..?
    I'm no expert on this, so just want your opinion..

    Thanks!
     
  3. largon

    largon

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    The mods will definitely gain you some MHz. Especially for shader domain clock which gives the most significant performance gain.
     
    quadomatic says thanks.
  4. quadomatic New Member

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    Thanks a bunch largon! I'll be looking into this then once I get my card.
     
  5. BUCK NASTY

    BUCK NASTY F@H Mod & 4P Enthusiust Staff Member

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    FYI, the EVGA 9600GSO Dual Slot has a different PCB design/layout than the single slot 8800GS/9600GSO. IMHO, it is a slightly weaker design/performance.
     
    Crunching for Team TPU More than 25k PPD
  6. quadomatic New Member

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    Crap...does that mean I won't be able to volt mod it? Or that I would have to figure out how to (might as well mean I can't...or maybe I could)?
     
  7. DOM

    DOM

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    just take the cooler off and take some naked pics of it like I did on the Palit 9600 GSO thread those are my pics if you didnt know, largon know his stuff ;)
     
  8. BUCK NASTY

    BUCK NASTY F@H Mod & 4P Enthusiust Staff Member

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    I have 2x 9600GSO dual slot's folding 24/7 and they score about 5-10% lower than the 8800GS. If there is a volt mod that would help the shader output, I'm onboard! I just ordered 2 more 9600GSO single slot's, as they are identical PCB to the 8800GS, thus better performance.
     
    Crunching for Team TPU More than 25k PPD
  9. DOM

    DOM

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    yes there should be a volt mod just post some pics for largon he should know what you need to do

    cuz the shaders run off the core volts

    I was getting like 6-7k with one card but im never on vista that much so thats why i havent folded in a while :eek:
     
  10. quadomatic New Member

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    Cool. I probably won't receive the card till some time next week though (paid newegg by money order, proly will end up shipping by monday or tuesday next week, so i'd get it by next friday). If pictures haven't been posted by then I'll try taking the cooler off. Hopefully it's not an incredibly difficult task to put take off and put back on. It wasn't real difficult with my X850 Pro, but then, that wasn't a dual slot cooler.

    Despite all the relatively risky (while actually not very risky at all) modding I've done with my current system, it seems to have paid off fairly well (Pentium Dual Core E2200+fsb locked motherboard+2GB Ram+HyperTX 2 Cooler for less than $100, cpu overclocked to 3Ghz by BSEL and vCore mod). This will be a nice cheap addition, proving that you can in fact play games on a computer well for very, very cheap.

    If I can handle Grand Theft Auto IV in November on my system with high settings, no AA at 1280x1024, I will be incredibly pleased.
     
  11. quadomatic New Member

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    My 9600GSO is supposed to come in this Thursday. I'll try to get pictures posted then.
     
  12. quadomatic New Member

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    Hey all, life has been fairly busy, and I was a bit fearful of taking off the cooler from my dual-slot eVGA 9600GSO. But, since I don't have a whole lot of time for gaming at this very moment (hopefully that'll change soon) I pulled my 9600GSO from my computer to take the cooler off and take some pictures. I'm running on my Intel integrated GMA950 right now...yikes.

    I tried to take as good pics as I could. The images are fairly high resolution (3072x2304), and in total all the pictures weigh in at almost 20MB, so I zipped them up and uploaded them to filedropper.

    It seems like I could overclock this card quite a bit. Without the volt mod, it runs at 752 mhz core/1806 mhz shader/1050 mhz memory. When I took the cooler off I found that the memory chips are Samsung, not the qimonda chips that were mentioned as being questionable earlier (though I don't know anything about the Samsung chips).

    For $34, it definitely seems like I'm getting my money's worth. Fallout 3 runs beautifully, as does most every other game I've tried (Crysis is a bit questionable, but that's to be expected).

    So, if someone could have a look at these pictures and tell me what I can do for a volt mod, I'd appreciate it:

    http://www.filedropper.com/9600gso

    Thanks a bunch!
     
  13. quadomatic New Member

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    So...has anyone taken a look?
     
  14. quadomatic New Member

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    bump?
     
  15. infrared New Member

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  16. quadomatic New Member

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    Ummm, yeah...

    The reason I posted the pictures is because the eVGA card doesn't have the same PCB layout as any of the other cards out there, which is why I needed someone to look at the pictures I posted of my card.

    Since my card has been sitting outside of my PC for about a week, and I've been using my integrated intel chipset for vga, if I thought finding a solution was as easy as Google, I would've found it already.
     
  17. infrared New Member

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    Ok, my bad.

    Lemme take a look. The voltage control chips should be pretty much the same.

    edit: your link doesn't work :(
     
  18. quadomatic New Member

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    DARNIT

    I'll find a better host.
     
  19. DOM

    DOM

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    http://www.techpowerup.org/

    File extensions allowed: gif, jpg, png, maximum size: 2 MB
     
  20. quadomatic New Member

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    There, they've been uploaded to Imageshack...I had to reduce quality of the images from 89 to 85 in GIMP though.

    I do wonder if the "N88GT-LF REV: 1.2" printed on the front of the PCB would help at all.

    Back:

    [​IMG]

    Zoomed (Left, Center, Right):
    [​IMG][​IMG][​IMG]

    Front:

    [​IMG]

    Zoomed (Left, Center, Right):

    [​IMG][​IMG][​IMG]
     
    Last edited: Nov 11, 2008
  21. infrared New Member

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    Interesting lay-out.

    The voltage control chip (for the gpu at least) is the RT8802A chip on the front-right of the board.

    http://www.alldatasheet.com/datasheet-pdf/pdf/207883/RICHTEK/RT8802A.html

    I'll have a quick look through the datasheet, but it's been a long time since i did electronics at college. Anyone feel free to jump in if you figure it out.

    EDIT:

    If you have a conductive pen you could do a VID voltmod which would be quicker and easier than using a pot. See pages 5-6 for the VID voltage table. Basically you set the gpu voltage by removing SMR's and bridging gaps.

    [​IMG] [​IMG]
     
    Last edited: Nov 11, 2008
  22. quadomatic New Member

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    infrared:

    Thanks for taking a look. I really appreciate it.

    If anyone needs better pictures of any specific part of the pcb, let me know.
     
  23. quadomatic New Member

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    Hmmm, I don't really know what the VID-Table says. Is it just that if there's resistance on some pins and none on others then the voltage will be different? So, I'd match up the resistor placement with the 0's being no resistor, 1's meaning yes there's a resistor, and the output at the end of the chart is the voltage I'd get?

    If I took too high of a voltage, then wouldn't I be kinda screwed since I wouldn't be able to put the resistors back?

    WOW, the picture makes those soldering points look big. Those resistors are absolutely tiny. I'm not sure how I'd go about removing those.

    Just as a size comparison, I put a penny next to the chip. Those points are TINY.

    [​IMG][​IMG]
     
    Last edited: Nov 11, 2008
  24. infrared New Member

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    You've got it. They basically ground out the pin, which would be a 0 on the VID table. If we can find a vmeasure point for the vgpu we can verify that.

    To remove them you can heat them with a soldering iron while lifting them with a fine pair of tweezers. I used to just crush them with needle-nose pliers lol. Use conductive ink to re-connect the pads. To make it more permanent when you have the desired voltage you can spray over the area with a conformal coating to protect it. Comes in an aerosol can you can get at any electrical shop.

    Ok, working from the table, if you 'open' the connection (1), the effect would be:

    VID 6 = +0.00625
    VID 5 = -0.01250
    VID 4 = -0.40000
    VID 3 = -0.20000
    VID 2 = -0.10000
    VID 1 = -0.05000
    VID 0 = -0.02500


    Hmm, I'll drop Solaris17 a PM. He should be able to help figure out a bit more.

    I'm off for the night (3:10am here lol). I'll take another look tomorow after work. Hopefully we can figure out a Vmeasure point, and then maybe the vmod for the memory.
     
    Last edited: Nov 11, 2008
  25. quadomatic New Member

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    Cool, sounds good.

    Just to check, how are we able to tell which side of the chip is facing "up", so we know which pins are the vid pins?

    Also let me know if you need me to read off the names on any other chips. I notice the names on the ones on the back aren't that visible.
     
    Last edited: Nov 11, 2008

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