The Simple & Concise 7900GT Voltmod Tutorial

[Keysplayr]

Originally posted by: weedmeister
eh...hello... newbie on the forum at your service...

just was wondering how good the "upgraded" stock cooling of this EVGA 7900GT KO would perform under all this OC'ing...

http://www.newegg.com/Product/Product.asp?item=N82E16814130015


would any of you guys know...?

and if I'm not mistaken, this seems to be the exact same fan they are using on their 7900GT Signature Series:

http://www.newegg.com/Product/Product.asp?item=N82E16814130018


seems to be the same card except for 100Mhz difference each on the core and memory and a $111 gap...


edit: another question, if i may, on the subjuct of cleaning the card with acetone... would this also benefit my mobo?

thanks

Three good things I see right away are that it's 1. Copper, and 2. cools the memory, 3.Is a lot larger (more surface area for heat dissapation. In other words, it seems to be a big improvement.

 

[dman918]

OK, so I have the same issue with ATI Tool. It artifacts like mad when I try to raise my core and mem. I am currently at 625/1700 and even there is gets an artifact every once in a while. Further, I am still having the problem of major slowdowns within BF2. I need to try Oblivion tonight or something, to see if it is isolated to this game or more. Everything is fine in RHTBLEHTNMGUSGHN (whatever - temps max at 60 degrees) and 3dmark, with good scores and no slowdown.
So....
What should I do? Of course test with Oblivion and see the results, but should I not use ATITool for the artifacting? Just use the above programs instead to test for stability?
Sorry to keep bringing this up, but I want it fixed.

 

[crazylegs]

I'm at 650 / 1700 temps are soo fine (luv my vf900!) hit 54c once after like 3 hrs of Oblivion, but ATITool never goes over 46C neither does RTRLDIR thing

At these levels i have ZERO artifacts in ATITool but did see some at slightly higher levels...

 

[inveterate]

Yo guys,, if i use the Coolbits registry hack on the Nvidia drivers. It lets me move the memory/gpu mhz WAY beyond the normal thing. is that just as good as the power strips and things u guys are using.

Like i can draw it to 1000 if i want to for the gpu. memory goes up to like 1500 but u double it..

 

[crazylegs]

hrmmm... my coolbits only lets me go to 800*2 = 1600

 

[straightalker]

Just curious. Does this modding of the 7900GT result in speeds comparable to a stock 7900gtx? If so, it seems rather bizarre that one costs 279$ on sale while the other 450-500$

Looks fun to mod but i'd be to afraid to try it. That's why i got an X1800XT.

 

[crazylegs]

Seriously the conductive pen mod is SOO EASY!

As far as reaching GTX speeds goes... almost but not quite - I'm @ 650 CORE 1700 MEM.

That is the exact same speed as a stock 7900GTX for core & 100 faster for MEM... BUT... the GTX comes with 512mb and not just 256mb or memory so has more bandwidth however bandwidth is only going to become an issue at VERY high resolutions and detail levels. (i.e. greater than my LCDs max 1280x1040)

But if you dont want to do any hard mods (no matter how simple they are) then i am sure the 1800XT was a great choice... you know u can soft mod that for volts and clocks though!

GL

 

[dman918]

Originally posted by: dman918
OK, so I have the same issue with ATI Tool. It artifacts like mad when I try to raise my core and mem. I am currently at 625/1700 and even there is gets an artifact every once in a while. Further, I am still having the problem of major slowdowns within BF2. I need to try Oblivion tonight or something, to see if it is isolated to this game or more. Everything is fine in RHTBLEHTNMGUSGHN (whatever - temps max at 60 degrees) and 3dmark, with good scores and no slowdown.
So....
What should I do? Of course test with Oblivion and see the results, but should I not use ATITool for the artifacting? Just use the above programs instead to test for stability?
Sorry to keep bringing this up, but I want it fixed.

Just tested the voltages: GPU @ 1.39v and mem at 2.23v...
Anyone?

 

[MAC5000]

I did the 1.4v mod, and I have a VF900. ATI Tool gets no artifacting at 650. I also have my mem set to 875. When I play Oblivion or FEAR at thoses levels, the 3D image will just go black after a short amount of time. The 2D stuff and sound on Oblivion will still be there, and FEAR will usually just crap out.

Does this just mean that things are clocked to high and ATI tool doesn't know what its doing?

EDIT: Ok, bumped my memory down to 850 and it seems to be fine now.

EDIT 2: Actually no, FEAR still craps out on me. Even at 650/850. Anybody know why only FEAR would do this?

 

[1Dark1Sharigan1]

Originally posted by: dman918
Just tested the voltages: GPU @ 1.39v and mem at 2.23v...
Anyone?

I would say don't worry about it if you don't encounter problems in games, 3DMark, RTHDRIBL, etc.

 

[moonboy403]

oblivion or ghost recon AW should be a pretty damn good indicator of system stability

 

[crazylegs]

Whats your PSU like....? If there is any chance of weakness in it bear in mind that an OC 7900GT could use up to 2x stock voltage also the vf900 could be draining alittle more juice than the stock HSF...

This may explain why u get errors during times of extreme performanc ei.e. Gaming..?!?

 

[dman918]

I have a Coolermaster 450w PSU. It seemed to work fine for the 15 minutes I played Oblivion though, runs smooth in 35dmark05 and 06, and RTHXXXX. I wonder if something is just screwed up with my BF2 install...

Tried running at 650/1800 and it locks in the ship scene of 3dmark. Also had a couple artifacts in the water. This was before I did the mem mod, so maybe I will try again...

ON EDIT: Oh, and back to the PSU thing. There isn't any special way to hook it up to the video card, is there? There is no PCI-E connection, so I hook two 4 pin power connectors to the adapter. I don't get the low power warning on startup. I have two entire lines of power dedicated to just the video card and VF700, if that matters...

 

[crazylegs]

mine is also usinh 2 4pin molex ---> PCIe adaptor... so should be OK!

not sure... but apparenty the MEM mod is VERY DODGY !!!

check this linkage out (took sooo long to find !!! lol):

http://forums.extremeoverclocking.com/showthread.php?t=219950&highlight=7900

SO YOU HAVE BEEN WARNED !

GL all

 

[dman918]

Well, I don't like that post. Maybe I should just get rid of the mem mod to play it safe. Regardless, I did not have the mem mod while having the issues I spoke of.
Thanks for the link. Probably not worth the risk if there actually is enough of one.

 

[firewolfsm]

Originally posted by: crazylegs
Whats your PSU like....? If there is any chance of weakness in it bear in mind that an OC 7900GT could use up to 2x stock voltage also the vf900 could be draining alittle more juice than the stock HSF...

This may explain why u get errors during times of extreme performanc ei.e. Gaming..?!?

The VF700/900 use LESS power since they spin slower...not that it really matters, maybe a 2-3 watt difference.

 

[crazylegs]

Originally posted by: firewolfsm

Originally posted by: crazylegs
Whats your PSU like....? If there is any chance of weakness in it bear in mind that an OC 7900GT could use up to 2x stock voltage also the vf900 could be draining alittle more juice than the stock HSF...

This may explain why u get errors during times of extreme performanc ei.e. Gaming..?!?

The VF700/900 use LESS power since they spin slower...not that it really matters, maybe a 2-3 watt difference.

fair enough i stand corrected. but i did say 'a little' in my case i have the vf900 plugged to mobo not video card... so thought somehow it my use more rather than just draining juice from PCIe slot...

 

[dman918]

So what are the thoughts on mem overvolting? Should I stay at 2.23v or go back to stock? I do not need every last drop out of the card, but do like performance increases if they are fairly significant.

 

[1Dark1Sharigan1]

Originally posted by: dman918
So what are the thoughts on mem overvolting? Should I stay at 2.23v or go back to stock? I do not need every last drop out of the card, but do like performance increases if they are fairly significant.

Only go a lot above 900 if your core can handle 700+ MHz. Otherwise, the core is not bandwidth deprived. So you won't get too much extra performance from an extra 30-40 MHz of mem speed.

 

[Muhadib]

Originally posted by: dman918
So what are the thoughts on mem overvolting? Should I stay at 2.23v or go back to stock? I do not need every last drop out of the card, but do like performance increases if they are fairly significant.

I like to get every single drop of performance I can get away with. Why not? <shrug>

 

[1Dark1Sharigan1]

Originally posted by: Muhadib
I like to get every single drop of performance I can get away with. Why not? <shrug>

You could damage the RAM chips since they don't throttle.

 

[dman918]

Hmmm... so with the mem mod, as soon as I started the artifact detector in ati tool, I got the flashing black screen. Wiped the chip clean and no flashing... weird...

 

[crazylegs]

glad u back to normal now!

 

[dman918]

Me too, but I do wish I could get better than 625/1700. Seems odd that with a VF700 and the memory heatsinks, I can only reach about that without artifacts.

 

[crazylegs]

its not the actual MEM that overheats if you have HS on them... with my vf900 on full and using the HS that came with it (aluminium not copper ones!) the HS dont get at all warm!

Its some of the other components that get MEGA HOT... thing they called mofats or something... anyway some of the other parts to do with MEM but not actual MEM chips they get hot as HELL... if i had any spare HS i would pop some at random places all over the card!

PS. my temps have only been taken using finger on various places when the card is OCed high and artifact testing! but trust me they some bits get way HOT!