7900gt overclock

[liquid51]

I know the volt mod is old news, but I was so pleased with the results that I had to start a new topic, rather than dredge up one of the old ones.

I used a circuit writer pen to take the gpu to 1.55v, and shaded the resistor to take the mem 2.2v. Using a zalman vf900, my temps are 38c idle and 63c load. My case circulation is garbage right now, so I think I could get those down a touch with a little fan rework.

Well, for the numbers:
I was able to hit 700/2000, rthdrbl stable and atitool artifact free for at least half an hour (stopped it there) =)

I was pretty nervous going in to this, but couldn't be more pleased with the results. I went from 500/1500 with temps at 46c/70-ish to 700/2000 with temps at 38c/63c. For my first major volt modded overclock, I think I did ok =)

 

[TanisHalfElven]

cool 700/2000. that as much memory speed as the x1950xtx. andd at probably better timimg. good card you got there.

 

[anandtechrocks]

I'm getting a 7900 GT soon too! What program did you use to overclock? Is it game stable? What do you get in 3D Marks '05? Lastly, what brand of card did you get (XFX, eVGA, BFG, etc.)?

Sorry for all the questions Thanks!

 

[liquid51]

It's an evga, and I was using coolbits. Coolbits limited me to 948 on the mem though, so I used rivatuner to push it that extra little bit to 1000mhz.

I am however running into a little problem with rivatuner though. It's not that big of a deal, but annoying non the less. When I initially set the mem to 1000, it says that the current driver can not support that clock. But the second time I set it, it has no problems. The nvidia control panel reports the correct speeds (700/1000), but rivatuner won't save those on reboot. The core is held at 700, but mem bumps back down to 790 after reboot. Anyone with riva experience know a fix for this?

I did let rthdrbl run at max res (1280x1024 on this crap crt ), 16xAA, while atitool scanned for artifacts. Riva reported an actual core speed of 720 and mem 999. Both ran for half an hour with no artifact. Temps maxed at 63c. (edit: it never did artifact. I just wanted to play eve instead of sit there and let it scan)

I play wow and eve primarily, and both games look simply glorious, with everything maxed, including 16xAA. vsync has me locked at 60hz (thx to my great monitor), but I'm usually always pegged at that 60fps mark. Doom3, although not entirley maxed, runs encredibly fast. I need to get oblivion and see what kind of havoc that gpu torture device will wreak on my card. Anyway, all games rock solid, and I play for hours on end.

No 3dmark yet. I need to tweak my proc a bit, but Ill see what I score. Have to wait till saturday at the soonest though. Im in FL till then.

 

[OCNewbie]

Very sweet, I think you've given me extra reason to go for the Zalman =) Wasn't sure which cooler to get for my 7900GS.

 

[lopri]

After volt-modding with a pencil or a conductive-pen, what kind of material can I safely use to coat the spot to protect for long-term?

OP: That's an amazing OC. Especially the 1000MHz memory part!

 

[imported_g33k]

A few words of advice: Do not overvolt the memory.

I fried a card this way. My gt was at 750/1950 with 1.55v on core and 2.2 on mem. I had 2 copper heatsinks and a 60mm fan blowing on the those small chips that regulate the voltage by the shaded resistor. My memory fried with less than 2 months of use. It was awesome while it worked though.

I went out and got another card, modded with 1.5v on core and got 680/1750 artifact free. I still overclocked the ram, I did not overvolt it though. No problems so far and I don't expect any.

You can see for yourself by checking those small regulator chips after 10 minutes at load. They get extremely hot! With mine they got damaged about week 6 or 7. Even manufacturers (eVGA, XFX) where mem is oc out of the box were getting a rash of RMA's with bad memory. So personally, I would oc the mem as far as it will go on stock volts and don't overvolt. The core you can go 1.5 or 1.55v as long as you have good cooling.

 

[Doctorweir]

Originally posted by: g33k
A few words of advice: Do not overvolt the memory.

I fried a card this way. My gt was at 750/1950 with 1.55v on core and 2.2 on mem. I had 2 copper heatsinks and a 60mm fan blowing on the those small chips that regulate the voltage by the shaded resistor. My memory fried with less than 2 months of use. It was awesome while it worked though.

I went out and got another card, modded with 1.5v on core and got 680/1750 artifact free. I still overclocked the ram, I did not overvolt it though. No problems so far and I don't expect any.

You can see for yourself by checking those small regulator chips after 10 minutes at load. They get extremely hot! With mine they got damaged about week 6 or 7. Even manufacturers (eVGA, XFX) where mem is oc out of the box were getting a rash of RMA's with bad memory. So personally, I would oc the mem as far as it will go on stock volts and don't overvolt. The core you can go 1.5 or 1.55v as long as you have good cooling.

QFT. The mem controller chips even get over 90C without voltmod...
http://img91.imageshack.us/img91/2144/tg2vf3.jpg
Courtesy to ontheotherhand from my german forum

My own RAMS got shot this way...without overvolting...when I first got the card, it made 950 on the mem, then bang...no more than 660 out of a sudden...with the coolers I installed on that chips now I'm back at 775...at least...but no more...

 

[Hail The Brain Slug]

What part number is your 7900GT, N56x or N58x? I know everyone has had success with the original 7900GT's, the N56x's, but I have not seen anyone trying it on the fixed 7900's, the N58x.
I have a circuitwriter in my hand, planning to voltmod my N584 later today.

 

[OCNewbie]

Do either of you have any links that show those 2 voltage regulator chips clearly? I plan on putting some sinks on them and want to have a clear view of which ones I'm aiming for. Thanks.

 

[Doctorweir]

You can take your glasses off before viewing this

Cool us!

backside of the card, far right corner with slot bracket on the left side...

 

[OCNewbie]

Originally posted by: Doctorweir
You can take your glasses off before viewing this

Cool us!

backside of the card, far right corner with slot bracket on the left side...

TYVM! It appears that is an Asus card from the jpg title. Aren't the Asus cards a non-reference design? If so are those regulators necessarily in the same spot as a reference GT/GS?

 

[Doctorweir]

This is reference...my XFX has exactly the same layout as Asus, EVGA and others...AFAIK only the Gainward Bliss 512 varies from the default design...

 

[imported_g33k]

Originally posted by: Doctorweir
You can take your glasses off before viewing this

Cool us!

backside of the card, far right corner with slot bracket on the left side...

Yep the two smaller IC's get the hottest. I have seen pics over on the extreme forums where overvolted, no heatsink, bare IC's, actually melted on to the circuit board.

 

[lopri]

Originally posted by: lopri
After volt-modding with a pencil or a conductive-pen, what kind of material can I safely use to coat the spot to protect for long-term?

Anyone?

 

[OCNewbie]

Do you even need to coat it? Maybe the graphite particles can fall off?

 

[lopri]

Originally posted by: OCNewbie
Do you even need to coat it? Maybe the graphite particles can fall off?

I think it's definitely possible. Besides, knowledge is power! It doesn't hurt to know which non-conductive (gooey but solidifying) material can be safely used on a PCB.

 

[liquid51]

there was an aerosol spray I used to use in some art classes when I was younger. We sprayed it on charcoal drawings and it "set" the charcoal, keeping it from smearing. I'm not sure what it would do to your pcb and components though. And if you happen to fry your card, what would the manufacturer say about the strange substance they found on your board?

When I shaded the resister and resistance was too low, I tried wiping off the graphite with my finger, very gently. One swipe took pretty much all of the graphite off and it jumped back up to 600+ ohms. So the stuff does come off easily. But hey, if it comes off after a while and you start losing stability, check resistance and stick some more lead on there. I don't think it will fall off on it's own though. Not unless something like a wad of cat hair gets up in there and wipes it off .

Oh, I did use a copper chipset heatsink (came with my vanteq hsf) on the IC's. I even put one on the IC's by the location of the gpu trace mod. Had an extra, so what the heck. So far, they just get a little warm. But they're definately not blistering .

 

[Avalon]

A circuit writer should be more than enough coating, I would think. It dries pretty quickly and holds on good. Used one to mod my Ultra-D to an SLI-D. It's been this way for almost half a year now.