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

[no_1_dave]

Carefull with the memory mod. The more you shade it in with the pencil the higher the volts. Start by only lightly shading it

 

[pinkacidbootson]

Carefull with the memory mod. The more you shade it in with the pencil the higher the volts. Start by only lightly shading it

Yup thats how i went about it, just shaded a bit at first, gave me 40mhz increase.

Then shaded as much as physically possible which gave me another 160mhz.

Should use a voltmeter really to be safe, but its your card. I didnt

 

[no_1_dave]

Did the 1.4 mod (3d mark 05 score in sig, didnt bench 06).
Clocked to 640/1600 easily. Now though in the morning it's back to normal. Its as if the paint wasnt even there. I can still see it there but it maxes at 560 core so i'm guessing i'll need to redo it.

Does the often happen or should it stay properly for good? I used the £8.99 stuff from halfords pictured earlier in this thread...

 

[man_from_uncle]

What an interesting problem. I guess the paint has dried and cracked somewhere breaking the circuit. It's not happened to me, but i guess redoing it should work.

You should also try pushing your memory further. At that speed it's bottlenecking the card slightly. You'll see significant gain by putting it up 100mhz or so.

 

[no_1_dave]

I would need to clock the core down a bit to put the memory up more, or do the memory mod which i'm a bit iffy about. I read somewhere memory at 1600 is fine till 700 core, then its a bottleneck

 

[man_from_uncle]

My own experimentation showed that a minor decrease in core allowed for a significant increase in memory which gave a significant overall boost in performance. I also got over 1800mhz without artifacts using using ATItool and I didn't hit my limit.

I suspect that if the memory is at 1600 it'll start to bottleneck the core as low as 580-600. I have no real proof (in fact I've not even reflected on it too much) but i did see a significant increase in performance by upping the memory past 1600; much more than I would have expected if it was not bottlenecking the core.

 

[no_1_dave]

I may try upping it a bit then & drop my core to 615 or 620.
I'll redo the mod this time (add a few touches) but if it does this again i'll just scrape it off, I dont wanna have to wonder if it'll work everytime I turn my pc on

 

[no_1_dave]

Ok, tidied up the mod & have re-done the contact points.
615/1700 scores in sig

46c tops with Zalman VF900 on lowest fan setting using rthdribl almost full screen

I'm happy with my £230 card

 

[kbc]

Ok, tidied up the mod & have re-done the contact points.
615/1700 scores in sig

46c tops with Zalman VF900 on lowest fan setting using rthdribl almost full screen

I'm happy with my £230 card

I'm on a 1.5v mod, and have tried 3DMark06 on 630/1800... seems to run fine, although some minor artifacts mentioned earlier on the snow test, so not really certain if I can class this as stable.

By the way no_1_dave, how long do you run "rthdribl" for to test stability? In fact how do you use such program? Just run it?

 

[man_from_uncle]

no_1_dave. Those are some great temps. A lot better than me. I go up to 49c with the fan on max (using ATItool).

You can probably squeeze a fair bit more out of that card though. I got up to 660/1850 or so stable for benchmarking and 620/1700 stable and artifact free for gaming, using just the 1.4v mod.

 

[Artheas]

Has anyone made a note of what temps they get with a stock cooler, at 1.4v, and 1.55v?

I used to have temps of 38-41/48 at 1.2v
Now i have the temps of 48/80+ at 1.55v


Getting a vf-900 tomorrow though, hope it helps as much as ive read it does under load

 

[no_1_dave]

I can bench at 650 but at 653 coolbits says no.
I can go higher through ATI Tool & Powerstrip but I get artifacts with ATI Tool at 640. I dropped it down to 615 because I didnt want the memory holding me back. 630/1600 got me 200 less in 05 then 615/1700

Dont want to do the 1.5v as i'm now worried everytime I boot up a game, going to take a few days to be sure the paint wont crack & break contact, so untill then i'll manually overclock it everyday instead of letting it boot up ready OC'd.

I ran rthdribl for about 20 mins. and yea, you dont need to install it. Just run it, grab the edge of it's window & drag it to the size you want keeping your nvidia control panel open on the temperature part so you can see. Then study for artifacts/go away & leave it, which ever you're most comfy with! To make things really heat up you can grab the centre of rthdribl & move the balls around with the mouse, moving really fast I managed to get my card to 48c

 

[no_1_dave]

no_1_dave. Those are some great temps. A lot better than me. I go up to 49c with the fan on max (using ATItool).

What case have you got?
I have an Akasa Eclipse with the front 120mm Amber @ 900rpm & the rear 120mm Amber @ 1500rpm. Also using an Artic Freezer 64 so the cpu air is blown right out the back. All running almost silent

 

[man_from_uncle]

Sadly I took my stock cooler off before I even tested it in my computer (very stupid thing to do). So i've got no idea how cool it would have kept the card. My underload temps though don't reach 50c with the vf900 so I think you've made a wise decision, especially as you've done the 1.55v mod already.

Dave, You've got pretty much the same balance as me now with your card. I'll be testing in the next day or so exactly what the highest stable point is. I'm hoping I can get to 625/1750 at least without have to do the next mod

 

[man_from_uncle]

I’ve actually got a very similar sort of air flow. Thermaltake Soprano case, 120mm fans front and rear, 80mm fan on the side and a Zalman 9500LED blowing air straight out the back air vent. I’ve also got an antec vcool blowing air onto the graphics card (though I don’t think it makes much difference really with the vf900 there). All in all it’s very quiet even with all the fans on max (I always use Zalman when I can). The only thing that restricts the flow is my hard disks. I’ve got 3 almost directly in line with the intake fan. I guess that might make a difference.

 

[no_1_dave]

My 3 hard drives are infront of my intake fan too. Doesn't seem to effect anything

 

[man_from_uncle]

Yeah, i wasn't really convinced that was it. It's probably one of those mysteries. I'm no expert at thermal dynamics.

 

[no_1_dave]

 

[Angilion]

Hmm...I think I need a Zalman. I get 61C max on stock, at 553/784 (card rated as stock 450/660). The stock Leadtek 7900GT fan is much louder than all my other fans, but it's a clean unvarying noise at a pleasant pitch, so it is far less intrusive than I'd expect.

My cooling will have something to do with the temps. To reduce noise, I don't have a rear case fan. Instead, I'm relying on my Akasa EVO-120 CPU cooler, which exhausts out the back of the case, roughly where the rear case fan would go. It's on minimum speed, of course, as is my 120mm amber for intake (fan controller).

I've decided not to try a volt mod. My system will be CPU-limited anyway (A64 Venice at 2.25GHz). So I can't give you temps on stock cooling with a volt mod. But hey, if you give me a spare 7900GT I'll volt-mod it and send you the resulting temps

 

[man_from_uncle]

Dave, I used to use that method of checking temperatures too and also found that i'd not exceed about 43-44 ish (max fan). But ATI tool pushes me further (and perhaps even measures in a slightly different way, i'm not sure) and after more than 10 mins or so of testing for artifacts I get 50 degrees, at which point it stabilises and wobbles between 50 and 51. Still if the stock cooler is letting people get into the 60s-80s I think I'm safe enough.