VOLTAGE Mod On A 7900GT?

A

aldy402

2[H]4U
Joined
Feb 23, 2005
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I did it on my 7800GT, anybody tried it on their 7900GT yet?
If its possible, id rather get the standard OC version from EVGA to save money and turn it into a superclock myself.

Does Nbitor recognize the 7900GT's bios yet?
 
I just read how to do it on VR-Zone. I am curious about this also since I watercool and these cores are much cooler. Here is a picture of what you have to do:

79gtvmod0ko.jpg


If you mod it soon let me know your progress, I'll have my card in 3 days and I might just Vmod it before I bother to put it in since I have access to everything required at work.
 
aldy402 said:
Does Nbitor recognize the 7900GT's bios yet?
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That's what I was wondering about. If the 7900GT is like the 7800GT, bumping the voltage by 0.1v should be easy with a BIOS edit and flash.

The power figures from the 7900GTX under load suggests it runs at the same 1.2v as the 7900GT. Why not just upgrade the cooling to crank up the GPU speed and worry about a volt mod later?
 
Jiggaman2576 said:
I just read how to do it on VR-Zone. I am curious about this also since I watercool and these cores are much cooler. Here is a picture of what you have to do:

If you mod it soon let me know your progress, I'll have my card in 3 days and I might just Vmod it before I bother to put it in since I have access to everything required at work.
Click to expand...

i rather do the softmod, i hate killing warranty, esp. on vcards

i sell them so frequently and the resale value just sucks
 
nibitor currently doesnt support the 7900 series. me and several other people at xtremesystems.org tried modifying the gt bios to have 1.4 volts and it didnt work. hopefully mavke (creator of nibitor) can crack it.
 
pandora's box said:
nibitor currently doesnt support the 7900 series. me and several other people at xtremesystems.org tried modifying the gt bios to have 1.4 volts and it didnt work. hopefully mavke (creator of nibitor) can crack it.
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im sure they'll be an update soon, or maby evga will release 1 for the 7900GT so some1 can mod it.

im sure its just a matter of time
 
They have figured out how to do the Vmod and its VERY easy to do the 1.4V mod. There are other mods that can be done to get you all the way up to 1.7V Google 7900GT Volt mod and you should find the site with the info. Linkage For those of us that are too lazy to read all the info on this, one guy reported going from 550 Core to 675 Core by doing the simple 1.4V mod. I am going to test mine tonight since that is what my core was limited to before as well. Happy day!

Jigga
 
I did the above mod, and am hitting 610ish core on stock cooling (need to change that, obviously) at 1.4v.
 
Yeah, if you look at the stock cooling on the GTX's, you'll basically need something like that or better if you plan on running at those kinds of speeds. What kinda temps do you get?
 
Currently about 60C +/- a few degrees depending on the exact load, but I have a low ambient temperature. I'm looking at getting a Zalman VF900 or similar.
 
Do the artifacts appear to be from heat? When I OC's mine too much without the Vmod I would get weird colors while running that rthdlib demo. If you are getting that then it probably means you need a little more voltage, otherwise its probably heat. 60C seems pretty cool for a video card but if you figure 90nm AMD cores are rated for around 65C stable before you start having problems then it does make some sense.
 
My artifacts are mostly glitching textures or polys, when I got them. Missing textures, oversized or misdrawn polys, and so on.

I haven't fiddled too much after volt modding though, due to lack of time. I let ATITool run for awhile at 610, and after an hour or so without artifacts decided it was good enough for now.
 
Kangg said:
Further in that same thread theres an even easier way to do a 1.4 vmod for the 7900 GT

http://www.xtremesystems.org/forums/showthread.php?t=92874&page=7
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PX Vertex said:
http://www.xtremesystems.org/forums/showpost.php?p=1355686&postcount=162

well, same post as ^ but this is what i'm gonna do
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great stuff guys, thanks....yeah, it's been a week or two since i looked at the stae of things with the 7900GT voltmods....seems that the 7800GT VR way was the problem, this way is much simpler.....gonna have to see what i can get out of mine, but 600/1800 seems weak now, shooting for 700/1800 at least
 
I did 1.55V mode on my XFX 7900GT Extreme (550/1.63). Running 720/1.94 temps 39C and 42C load, but planning on running 700/1.9 24/7. Maze4 LP and some ramsinks. So far so good. it was an easy mod. I hope unmodding will be as easy. I used conductive ink to connect 32->31->30 and 21-22 pins. Thanks to xtremesystems.
 
I did the 1.4 Mod yesterday with the 1 wire at the top of the board. Went from 550/1600 to 640/1880. My temps went up to 38C under full load though, from 32C which seems high as far as the difference. I don't think I did that great of a job on the thermal paste, so I'm going to reapply tonight. I started getting artifacts at 650 after about 40 minutes or so, and it wasn't weird polys but green text looking stuff popping up in different area's. I really think it was heat related, like there is a hot spot on my chip.

On a different note, how safe is it to run a chip like this at 1.55V because I'd have no problem doing it if it could handle it for atleast a year :)
 
Jiggaman2576 said:
On a different note, how safe is it to run a chip like this at 1.55V because I'd have no problem doing it if it could handle it for atleast a year :)
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With good cooling I'm expecting it to run a few years.
 
this voltage mod stuff has me interested. Can you voltmod with air cooling (Zalman vf700cu)?
 
Jiggaman2576 said:
On a different note, how safe is it to run a chip like this at 1.55V because I'd have no problem doing it if it could handle it for atleast a year :)
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It's a 90nm process, just like an AMD processor. You should be ok for at least a year. :)
 
I just finished doing the other 2 simple volt mods near the edge of the board. I should now have 1.55V to the core, but I wont be able to verify till I get home. I also had a friend piggy back a 100K ohm resister onto the are marked as K below. Doing this changes the refresh rate of something, I didn't read that closely but its important if you want to hit above 700mhz on the core. Here are the mods taken from the guys at extremesystems:

voltmod27mm.jpg

voltmodcopy8ei.jpg


I used solder to do these, probably not all that smart but then, I am risking the board and I have no intentions of trying to trade it for a new one if I fry it. If I sell it, it will just be an added feature that I can charge more for!
 
jbean7457 said:
this voltage mod stuff has me interested. Can you voltmod with air cooling (Zalman vf700cu)?
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Sure can, the only issue being heat. Just make sure that everything is staying within spec temperature wise and you've got good airflow.
 
glad my Thermalright V1 Ultra will move from my 7800gt to 7900gt :)

my 7800gt with a 1.5v mod running 540/1280 never even hit 50*c fully loaded
 
Silverado SS said:
where can I get conductive ink? Would AS5 work to make the bridge? Are there no softmods out yet?
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Go to auto store and get Rear Window Defogger Repair Kit.
 
thats what i have! will do the mod. already have my 7900GT CO SC but waiting for my SN25P to come.
 
I managed to pull off 710mhz on the core with the 1.55V mods in place. I had to lower my memory to 1580 (790) to get it to stop artifacting. I have some ramsinks on the way and a slot cooler that I hope will cool them off so I can run them faster again. Almost broke 11K in 05 however I am not running my ram 1:1 so I have some G.Skill 2GB PC4000 on the way that should do up to 275 1:1. I'll report back but so far this is the easiest mod I've done with the biggest performance gain. If you got the cooling, you should atleast do the 1.4V mod to make it the same as a GTX.
 
Jiggaman2576 said:
I managed to pull off 710mhz on the core with the 1.55V mods in place. I had to lower my memory to 1580 (790) to get it to stop artifacting. I have some ramsinks on the way and a slot cooler that I hope will cool them off so I can run them faster again. Almost broke 11K in 05 however I am not running my ram 1:1 so I have some G.Skill 2GB PC4000 on the way that should do up to 275 1:1. I'll report back but so far this is the easiest mod I've done with the biggest performance gain. If you got the cooling, you should atleast do the 1.4V mod to make it the same as a GTX.
Click to expand...

did you try doing the mem vmod to keep the memory up there instead of backing off ?

seems like alot of people are hitting 700/1800 stable
 
Jiggaman2576 said:
They have figured out how to do the Vmod and its VERY easy to do the 1.4V mod. There are other mods that can be done to get you all the way up to 1.7V Google 7900GT Volt mod and you should find the site with the info. Linkage For those of us that are too lazy to read all the info on this, one guy reported going from 550 Core to 675 Core by doing the simple 1.4V mod. I am going to test mine tonight since that is what my core was limited to before as well. Happy day!

Jigga
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That's a great thread Jigga, thanks for the link. The 7900GT 1.4v and1.35v mods are sooo easy.
 
I haven't done any Vmem mods yet, and I am not sure I want to risk frying it. They run so hot already, more heat would suck. I think I just have to break it in, I ran it at 1800 lasntight again and I had no problems.
 
Jiggaman2576 said:
I haven't done any Vmem mods yet, and I am not sure I want to risk frying it. They run so hot already, more heat would suck. I think I just have to break it in, I ran it at 1800 lasntight again and I had no problems.
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what u using to OC? my coolbits only lets me go to 530/816 :(
 
gurgle said:
what u using to OC? my coolbits only lets me go to 530/816 :(
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coolbits lets my 7900gt get higher than that :confused:

I'm gonna try the 1.4 voltmod some night this week. My temps are already great (don't break 50c load). But damn it makes me nervous as i've never voltmodded before... the thought of high 600's is too tempting.
 
the conductive pen one seems pretty easy too, and is reversible. im gonna try that as soon as i can find some conductive pens.
 
I just bought a conductive pen a radio shack ($12.99) i'll post in here with results as soon as I get a chance to do it. :cool:
 
jbean7457 said:
I just bought a conductive pen a radio shack ($12.99) i'll post in here with results as soon as I get a chance to do it. :cool:
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excellent. you running stock cooling? i want to do this too, but i havent found a good aftermarket cooling solution yet.
 
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