My cards did 585 on stock, just put waterblocks and 1.4v on em, testing it out.
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My cards did 585 on stock, just put waterblocks and 1.4v on em, testing it out.
The Samsung chips used on these boards are spec'ed to run at 1.8 Volts, with a factory (Samsung) recommended maximum of 1.9V. Board vendors are shipping them at 2.0 Volts, and there is some speculation that this is leading to the relatively high number of returns for these boards. Samsung does not publicly guarantee operation above 1.9 Volts and says that they can be damaged if exposed to more than 2.5 Volts.Quote:
Originally Posted by Willis
I don't know if there's anyone here who can guarantee you anything other than what's on the data sheet for the part (which is what I've quoted above). The board vendors are already overvolting the part by .2V (but not more), so you may be able to infer something from that.
Now that is interesting.. no vmem mod for me then. lol.
I found out the same info as you but thought I must have just misunderstood it because all of these board companies are shipping out GT's with significanlty higher voltage than what the IC's are spec'ed for? I'm not expert with this stuff but I wonder if some of us who have experianced multiple RMA's with their 7900GT but continue to get crappy cards if it would be beneficial to undervolt the memory? Obviously all of my artifacting problems are a direct result of the card's memory (not just from reading these specs, but from testing and tweaking). When I underclock my memory everything runs fine)!Quote:
Originally Posted by sluggo
Hehe, that's good for me as I get 1800MHz on my memory chips. :cool:
That must be the reason why feeding the RAM more volts overclock gets worse.
I'm stuck at 1790 (how frustrating wanting 1800 :mad: ) at stock voltage (2.02V)
At 2.06V it maxes some where around 1780, 2.09V results in 1680 max.
If only i could lower the voltage a tad...
No misunderstanding, the Samsung K4J553232QG-14 that everyone is using (http://www.samsung.com/Products/Semi...23qg_rev12.pdf) is being overvolted by the board makers. I'm sure they've discussed it with Samsung and have reached some sort of agreement (Samsung may even have a revised spec in the works for all I know), but yes, as of now all the board makers are running the parts .1V over maximum recommended operating voltage.Quote:
Originally Posted by Roger_D25
I'm not sure how to go about undervolting the memory on these boards but it would be an interesting test. I've no doubt that the board makers have done all the characterizations that can be done and are shipping the fastest configurations that their agreements with Samsung will permit. Whether Samsung has properly characterized the 2V operation of their part is another matter, and is bound to be a subject of current discussion between Samsung and eVGA, XFX, etc.
I bought some electical repair kit stuff.. but the consitency was terrible, like chewing gum, and it didn't stick to anything, and much less lead any current. Maby using a hair dryer on it will help? Tried some soldering as well, but it's far too tiny! For gods sake: 0.5mm pads about 9 mm apart.. hopeless without microscope and special equipment! Or the skills of someone like persivore :)
I think maby I've damaged the top D511 pad, are there any points nearby that should have the same connection, so I can check with beeping if there is still any connection? The same point on the bottom row maby?
Can anyone who has done the conductive ink mod measure the resistance between the D511 point and ground? Thanks very much!
Too tiny?Quote:
Originally Posted by Marlowe
http://img.photobucket.com/albums/v6...s/IMG_1917.jpg
..or the skills of someone like Zeus :)
Near impossible for me.. my thumb would fill that whole picture! Even difficult to see the details of that without macro mode of a camera or a good magnifying glass :p:
However pretty smart to lay the cable like that.. would make it easier I guess.
That "cable" is just a tiny wire from a rounded ATA cable. :D
Did the soldering without magnifying glass but i have to admit that the soldering pad is very small, no room for error at all.
Yeah cable / wire - excuse my English :p:
I will machine the tip of my soldering iron to an extreme (put in English word for sharp end of something) and try again when I get home.
I know my English sucks! arghh :mad:
Don't worry about your English Marlowe, your doing a great job! If anyone gives you crap just ask them what their second laungage is, lol! Now back to business, sharpening the tip of your soldering iron can help alot, at least it did for me. I bought a few of the smallest tips I could get for my 25W iron and using a file I shaped the tip to make it as easy as possible to solder tiny components.
I also use a magnifying glass along with a third-hand tool which made a huge difference for me! Last but not least, the best way to get comfortable with soldering tiny components just practice on an old NIC or graphics card that you won't use any more. That is what I did before getting near my 7800-7900series cards!
Zeus - When your soldering those tiny componest and pads, how exactly do you do it yourself? Do you usually tin the tip of the wire and then just put the wire on the pad and then touch the iron to the wire? This would keep unwanted heat away from board and you wouldn't have to feed any solder to the joint. Now I've done some voltage mods to cards and motherboards in the past but it's always a stressful project, do you have any tips or how-to's for a somewhat expereinced modder? Thanks guys, as always your help in this forum as been very useful.
Marlowe, i din't mean to bash on your english, it's pretty good actually.
Roger, yes that's basically how i go about but i like to keep the tip of the soldering iron a bit longer in place so that the soldering pad on the pcb melts and the wire joins in on the soldering pad when it's cooled of.
I want the wire to hold secure, if you just heat up the wire and let it sort of "stick" onto the soldering pad chances are the wire might come loose, the thought of that scares the hell out of me.
I'm using a fine tipped 25W soldering iron, i did not sharpen the tip, i'm just using it the way i bought it.
Actually, i think 25w is a bit much, i plug the iron in, let it heat up till it melts a piece of tinwire easy, clean the tip with a wet sponge, unplug it, let it cool down for some 20 seconds and then i do the soldering.
That's the best way to do such delicate Vmods imo.
Furthermore, for such small soldering pads one needs a very fine wire, i found that a single wire from a rounded ATA cable suits in nicely.
And most important, don't rush things, always doublecheck you didn't short anything with your soldering before firing up.
All good points Zeus, thank you very much! When I tried my first voltmod I just bought the smallest gauge wire I could find at the local electronics store, only after I got home from store did I realize that I already had an abundant supply of the perfect wire, old IDE cables, lol! When you use these old IDE cables do you try to use a single strand cable or do you try to find and use an IDE cable with multiple strands so that the solder will stick better?
I also think that 25w is too much, like you I need to constanty plug/unplug it to monitor the temp correclty. Like I'm sure you know, when the iron is too hot the solder just balls up and falls off and gives horrible contact in the wires, isn't the solder suppose to "suck into the wire" for the best contact?
Thanks Zeus very much for your help! Over at Guru3d where I spend most of my forum time there are many end-users who have been having problems with their 7900GT's. I havn't seen too many people posting about their GT's having these problems (although I don't browse too much here at extremesystems.). I'm refereing to the artifacting, freezing, not being able to use the "Detect Optimal Frequencies", computer needing to be manually restarted after exiting games becasue of massive artifacting and blinking screen on/off.
Everyone who has had issues with their GT's have basically had these same problems. Also it seems that these problems only begin after a day or so or perfect card operation?
Did you ever expereince any of these problems with your EE or has your card been working perfectly since you bought it? A member over at guru3d told us about his converstion with an eVGA tech who said all these problems are been identified and is currently being investigated and should be fixed in the next 2-4 weeks (so I'm holding off on my forth RMA). The other thing the tech said is that the problem has to do with the switching frequency not being high enough to keep up. A very smart member here named "t024484" came up with a mod to increase this switching frequency, he said that doing this mod cleared up all his issue and allowed additional stability when voltmodding?
Hehe thanks guys. Don't worry Zeus, I wasn't really angry. Also I know it's wire not cable when I just think about it.. it's just the same in Norwegian :p:
Anyway I did the mod and it works. I was unsure if I should post the pic, cause I knew I would get some remarks about my trailer load of tin :D Also you can see the missing D511 pad I told you about..
http://www.home.no/oomg/gfxmodd.JPG
Again sorry for slow loading of the picture. I've got a 15W iron wich I've bought a pretty sharp tip for. I realized I wouldn't get it much sharper than it was.
I also lowered the resitance K from 84k to 45k sharp as suggested in the second post. The 1,55V gives me around 695 core.. 700, 720 and up seems to make the card throttle down. I also have to keep the temp below 50 or so to make the high clocks work. Wich means side panel off and full speed on fan.. This gives me around 11k in 05: http://service.futuremark.com/compare?3dm05=2033228
I can offer a little bit of advice on board rework. In no particular order:
- Heat the work first, then add solder. If you just melt the solder on the tip and then try to put the solder on the connection, you will make a mess and will likely end up with a bad connection. Make sure the two things you are joining are heated up and ready to accept the solder first.
- Pre-tin wires. Can't say it enough. If you you pre-tin the wire you can often make a connection without adding solder at all - how easy is that? To pre-tin, just heat the end of the wire and touch solder to it until the wire is holding all the solder that it can via surface tension.
- Keep a wet sponge next to your solder station and wipe the tip each time you pick up the iron and each time you set it down
- Do your work in a well-lit area. Have a magnifying glass handy, and if you have a third-hand available, use it to hold the magnifying glass over the work so you can see very clearly what you are doing.
- Buy a couple of sticks of hot melt glue. After you solder one end of a wire in place, wipe the tip of your iron against the end of the stick and put the drop of glue on the wire/board near the first solder connection. This will prevent any stress to the first solder connection while you solder the other end of the wire. Add a drop of glue to the middle of the wire if it's a long run.
- If you are doing a lot of wiring in a small area and are working with low-current signals (logic, volt-modding, etc), you can use 30 AWG wire-wrap wire. It's very thin, very flexible and has a tough urethane jacket.
- For general work I like to use stranded wire with teflon insulation. Teflon is nice because (unlike PVC) when you get the wire hot, the insulation doesn't shrink, melt, or deform. You could put the soldering iron directly on it and it won't move. Great stuff.
- Use the finest tip that the work will allow. A small tip puts the heat right where you need it and nowhere else. With a fine tip you can do anything on a PCB that you need to do with as little as 15 Watts.
- One good solder tip will last longer than five cheap ones.
- Put solder on the tip and THEN turn the iron off. The solder will prevent corrosion.
- Don't blow on or sponge a hot solder connection to cool it. This can lead to a bad connection. Let the solder cool on it's own.
- Only use rosin core solder - never use acid core. Acid core is for not for the kind of work we're doing and will enentually destroy the connection your are trying to make.
- Do not "clean" a finished connection with alcohol. This only spreads the rosin around, which can lead to problems in humid environments.
- People may try to tell you that silver solder is the best. Ignore them. Silver solder is a pain in the ass to work with and gives you no better results than standard 60/40. Silver solder is mainly useful for non-electrical work and where the solder needs to be polished later.
- Buy some standard tools and use them: solder-wick for cleaning up surfaces, a solder sucker for clearing through-holes, and heat-shrink for wrapping wire connections
Okay, enough, I'm starting to blab now. Good luck =)
There you have it, plenty of very helpfull tips, great stuff Sluggo!
Roger, to answer your question, i prefer the multistranded as it's more supple so easier to work with plus it sort of sucks up the solder whe you pre-tin it.
Marlowe, your pic didn't work for me, glad your mod worked out fine now. :up:
edit: pic works now.
Sluggo - yes, great info. That should go into the OP as a "read this first before modding" intro. :)
EDIT:
hehe.. the new vmod will be to lower the memory v. ;)Quote:
Originally Posted by Zeus
i only used conductive ink, and given the concerns about soldering, I don't know why you would want to if only doing a direct 1.4 to 1.55 volt mod, as the ink is easily removed and risk free (unless like anything you short something out).
Just my 2c worth.
I must have the weirdest 7900GT of all time. :confused:
Feeding the mem more voltage results in (much) worse overclocks on the mem and today the card had a new surprise for me.
I already have a small wire solderd between resistor D511 and ground which gives me 1.4Vgpu, no problem so far.
Today i soldered another wire to resistor D508 and ground and guess what?
Still 1.4V!! :confused:
After that i tried the +0.05V point and ground....1.4V and nothing more.
I studied the pictures a thousand times so i'm sure i took the right spots.
As for ground, ground is ground right?
WTF???
Have made the pencil mod on DRAM and the 0.2+0.05 GPU VMOD and have some serious problems. After I OC the card my screen starts to blink and lots of artifactcs even in windows. So have removed the GPU vmod but the problem is still there. Have removed also the pencil mode but notthing happend...still the same problem. The card is doing ok with GPU OCed but when I overclock the ram even for just 1mhz over the stock speed the screen starts to blink and the artifacts over all screen...anyone has similar problems? The point is that at stock speed it is all ok...and I cannot RMA the card...because of this.
Regards,
Primoz
I have now had 2 customers KILL their 7900 GT.
Every time it happens because they turn up the Vmem.
I think it is because of the resistor K mod and the Vmem.
I would strongly advise agains doing both of them.
BTW it is the same chip that blows up on the erliger cases in this thread.
BTW2
NOW WHERE THE F´´K can I geet that and what is 30 AWG wire-wrap wire?
"- you can use 30 AWG wire-wrap wire.
- For general work I like to use stranded wire with teflon insulation. "
Google is your friend. The teflon is not cheap, but you can order in any color you like (with or without stripes) at http://www.weicowire.com/specpage.asp?nGroupID=150
Wire-wrap is common as dirt. I'm sure radio shack would carry it, but if there isn't one nearby, try http://webtronics.stores.yahoo.net/1030awgwiwrw3.html
Wire-wrap is (was) used to speed up prototyping of digital circuits. Parts were inserted into a grid of sockets, and the socket pins were wired point-to-point with this wire and a wrapping gun. No soldering and easy changes. Old School.
Hey Guys,
First of all thanks for your post sluggo (soldering tips),although I have come to use many of them over time but wish I had read somethink that like years ago! I have also used the silicon insulated wire, this stuff is just great. Once you use it you'll never go back to the regular stuff.
You guys probably already know this but many people have been having problems with their 7900GT's, and not just from failed attempts at voltmodding. People like myself who have gone through multiple RMA's and still are having the same exact problems with their cards. The problems are mostly artifacting, freezing, bland screens, and crashes to name a few. The funny thing is these problems only start after a few days of perfect operation.
Well eVGA has been the first to officially offer new "Slighty modified" cards as replacments to the people who have had these problems with multiple cards. On their message boards they had a form that registered eVGA owners could log onto and fill out about the problems we have been having. They are being very proactive about this and have really impressed me. I just filled out the from last night and I got a response today. Jacob Freeman wrote me saying that they know what the issue is and that it's hardware based (cannot be fixed with BIOS/software update so they need to be replaced). They said they have a done a slight modification to some cards which has fixed the problems and the cards they will replace ours with will be at 100%! Not only that but their offering Cross-Shipment RMA's to boot, which means their shipping out the fixed cards first, then you have 30-days to ship defective card back to them.
There is some great info over at guru3d in their Nvidia Graphic Card section as well as over at eVGA's message boards. If you think your suffering from these problems and have not modded the card then check it out! I can't wait, I've been unable to do any stable gaming since I bought my first 7900GT about 2 months ago, despite the fact I'm on my third RAM replacement card!