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****The Official 7900 overclocking thread****

kbc said:
Hi vocch... I'm currently testing on 1.4v, are you sure cooling with a Zalman VF900 is sufficient for hitting 1.5 volts?

When was 1.5v needed and at what core speed was it required?
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Hi...i benched up to 665 @ 1.4v and @ 1.5v got me up to 705....and the zalman should be ok although i used a desktop fan for extra cooling and at 1.55v highest temp was 55.....without you should reach around 60's at a guess.
 
vocch said:
Hi...i benched up to 665 @ 1.4v and @ 1.5v got me up to 705....and the zalman should be ok although i used a desktop fan for extra cooling and at 1.55v highest temp was 55.....without you should reach around 60's at a guess.
Click to expand...

Hmm.. I'm on 1.4v at the moment, and have benchmarked it using 3DMark06 with a Zalman VF900 and I got small artifacts on the last "snow" test, not huge - this was putting the core at 640MHz and stock memory settings of 1650MHz - 1.5v also generated the little artifacts on that last test, bearing in mind that temps were no higher than 65C.

Running Source seems ok. But I would like 3DMark to run completely artifact free. :(
 
man_from_uncle said:
At 650/1784 3dmark05 10824. Getting to 11,000 will be tricky.
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Nice going so far...is cpu clocked at max....if so give 1.5 then you'll be sure to get 11k. :)

@kbc...are you getting artifacts at lower clocks?..and what you getting at 1.5v.
 
Vocch he was getting them at 1.5v too, I was a bit surprised. :eek: Using coolbits caused the system to crash when we hit the test button, had to boot with system disk. So we had a go at ati tool and that worked up to 640/1650 where he got artefacts on snow test.

We stoped at 640 on 1.5v because of artifiacts. :confused:
 
Has he made sure that paint ain't making contact with any other points....one way is to take a photo of mod and zoom in...as it is hard to tell by eye.
 
I put the paint on for him and was very cartful not to hit any other pins. The masking tape method failed as it pulled of the paint when removing it so had to do it by hand.

I will get him to have another look at it.
 
660/1820 - 11029 3dMark05 very very minor artifacts. And I think at that i'll call it a day. Max temps just short of 50c. Going to run Oblivion now and see what the highest stable overclock I can play at is.

My CPU is only at 2.7ghz and it certainly will go higher without too much hassel, but i've just got it it's rock solid at this speed and I'm a little nervous about dicking about with it again.

Very pleased indeed though. My mates SLi 7800gtx set up only gets a little higher than that.
 
Hi people! My first post here at OCUK so i thought i'd jump straight in at the deep end! recently swapped out my 7800GTX sli setup for 7900GT sli and am looking to do the 1.4v mod to boost pefromance on these little beauties even further.

Thing is, i was wondering what the best way to test how many volts are running the the core is? i've seen other people refer to voltmeters, but how do you connect these up? any help would be very much appreciated!
 
OK...

I'm back on 1.4v at 630MHz core... and have scraped off the paint for 1.5v since it artifacted, and didn't want the extra heat if I couldn't get higher clocks.

If I run "just" the snow test on 3DMark06... it would run fine without artifacts.

But if I do the complete test for a 3DMark score (i.e. running all the GFX and CPU tests)... the last snow test would generate very, very minor artifacts. I have tried it on Source and it seems to run fine... but I'm not too sure if I can class that as a stable overclock.

I will try and get a picture of it to show you the volt connections...
 
man_from_uncle said:
660/1820 - 11029 3dMark05 very very minor artifacts. And I think at that i'll call it a day. Max temps just short of 50c. Going to run Oblivion now and see what the highest stable overclock I can play at is.

My CPU is only at 2.7ghz and it certainly will go higher without too much hassel, but i've just got it it's rock solid at this speed and I'm a little nervous about dicking about with it again.

Very pleased indeed though. My mates SLi 7800gtx set up only gets a little higher than that.
Click to expand...

Well done...i don't think there's any need either to spoil your o/c for an exra couple of hundred points...nice to see you hit your goal. :)
 
KWJay, to be honest I have no idea where/how to test for volts with a voltmeter or otherwise. I do however have faith in the fact that this minor hardware mod that can be done with a bit of conductive paint and does indeed up the voltage just the right amount.

I should say though that the pen I bought was utter rubbish and I couldn't draw a line with it at all. I ended up getting a big dollop of it near the right places then used a pin to spread it an connect it correctly. It took me nearly 30 mins, though 27 of that was just getting the ink out of the pen.

Just played Oblivion too all maxed (HDR, no AA) at 1600x1200 with 600/1600 all stable and pretty darn smooth (though not perfect). Might try upping the frequencies a bit but I'm guessing that 620/1700 or so will be the limit that'll play without crashing.
 
7900GT "easy mods"

I sold my old 7800 gtx and got 2 of these 7900 gt's. One is watercooled and one is still on stock cooler...I was able to clock both to about 540-550/1600 on stock volts......Did the volt mod to 1.4 and was getting 630-640 out of both cores, no tmuch increase in heat...extra mod to 1.5 and was able to get 660 out of one, and 700 out of the other....strange though, near 700, i can hear a high pitched data "noise" coming out of one of the cards....but both are stable at 660/1650.... need to mod memory now though :)...on standard driver settings with no changes, got 6000 per card 3dmark 06, and 9500 on sli......probably get 10000 if i changed driver settings :)
 
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