An overclocker/modders dream come true - 7900gt?

Question

I have been reading about the simple conductive pen volt mod for the 7900gt to get it to a 7900gtx level of performance...wow...if true and this easy, this could be an all time overclockers/modders dream come true.  So if you thinking about upgrading and willing to mod your vid card, this may well be the card to get!
Here is but just one discussion with pictures on the volt mod for the 7900gt.  I know that this will void my warranty, but isnt the risk worth the benefit?  I wonder if nvidia will try and "fix" this so you wont be able to do it in the future.  Anyway, Im waiting another 60 days to see if these users start reporting blown cards so I just dont happen to mod mine too soon...any comments?
http://forums.guru3d.com/showthread.php?t=176625

Answer 1

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The picture you provided looks far simplier than the first one I posted in the link I provided.  Was this because later you or users traced it back to this one chip and pins?
Actually it started with the chip.  After looking at the white papers it was discovered it was a binary input VRM setting the output voltage.  The concern was that the pins are so small that beginners/intermediate users will not be able to solder or short the pins.  Those pins were later traced to areas of the board where the user has more room to work.  I thought the d511 to that ground pad was the easiest way for the masses to get 1.4v so I posted the "yellow line" picture.  There are tons of ways to do the various mod, I have seen other ways to get the extra 1.15 volts for 1.55v total that maybe more appealing to your style of modding.  The way I did it was the d511 to ground yellow line which gives 1.4v, then also the shorting of pins 30-32 on the chip to get the 1.55v, both mods are required for 1.55v.  The 2nd part of the mod in the picture I posted here is actually a bit more patience inspiring then you would think.  Those pins are small.  I use a sewing needle with so little conductive paint you could hardly see it and I still got a pretty big blob on there.
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In some of the other threads on either xstreamsys or guru3d, they talk about modifiy the card greatly to get to 1.7 or more volts...but when I look at the difference in performance of a pen/paint mod which is reversable and a 1.7 mod, I dont see a huge increase in performance.
The 1.7v mod is only for the extreme user.  It requires soldering and is not worth it in my opinion.  You are effectively changing the chip to read Intel VRM code from AMD VRM.(So you get output options up to 1.7 with the same binary inputs.).  I also think the gains are minimal to pump that kind of voltage through the chip.  The damage possible is not worth a few more clocks. 
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I also read somewhere that these 7900gts shouldnt go above the 1.4 volts....how true is that.
The core themselves are the same, so 1.4v(default for GTX) is beyond a doubt safe.  Going above that...same as overclocking the CPU I suppose,.... risk is involved but staying around 10% or lower overvoltage probably will not shorten the life of the card enough that it will be obsolete before it dies. 
There was some initial concern about the fact the voltage regulators are different on the GT's then the GTX's.  I forget the numbers but I measured temps from 1.2v to 1.55v with a contact temperature probe and noticed a slightly evelavated temperature(something like 5-8C) on the mosfets and chokes.  Supposedly the overcurrent protection will shut them down if they draw more current(making the heat) then they can handle by design.  This one I'm not so sure about.  It very well could shorted the life of the card drastically, not the GPU but the voltage regulator.  It may be a time will tell thing, however I haven't heard of any deaths do to a properly done mod yet but it's only been a month and a half.  Personally I didn't see anything getting so hot that it had me concerned that immediate death was coming.
1. I either use a conductive pen or window defogger repair kit.  I think it's harder to remove the window fogger once dried though but it still comes off.  I got my pen at Fry's Electronics but they don't have Fry's everywhere, they might at Radio Shack.  The window defogger repair kit is in most Auto Part Stores.
2.  I'm not really sure about the Zalman 700.  What I would do is the 1.4v mod from d511 to ground.  Run ATI Tool and monitor the temperatures to determine if you are going to have the cooling capacity headroom for 1.55v
3.  One of the cards I had could only do 640 at 1.4v, still a nice improvement from the 580Mhz it could do at stock 1.2v.  Like I said above I would try 1.4v at see what it gets you.  If you are 650 +/- 10 then I'd just stop there.  You then end up giving the card alot more volts for smaller gains.
4. Yes I like ATI Tool. If you are artifact free in it, usually I notice no issues in games.  Not that I play tons of games though...
I also recommend a multimeter, but not necessary.  I like to verify my work.  Checking continuity between my shorted pins, and isolation from pins near the mod.  There are pictures that show the test point for Vgpu also.