When does OC'ing start to hurt?

lobstar

Limp Gawd
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I don't claim to be a Gawd or anything when OC'ing, and I know the general ins and outs of the procedures, science, etc,. My question is this:

When I run y BFG 6800 OC, unlocked to 16x6 I get the best performance at 360/750 for my oc ... not much to brag about. The problem is lets say I kick it up to 390/790. I get no artifacting, temp only goes from 51c to 58c under load, and I score much lower FPS in games and benchies. Went from 17k and 4k in 3dm01 and 05 respectively to 16k and 3200 after that OC. Now I didn't clean bench, meaning I did not restart the PC, but I did allow the card idle time to cool down. Is this normal or explainable? What are the reasons if explainable, and am I the only one seeing this? Is there a point where if I go higher I will start to go back up? I am not too keen on volt modding the card, but just want to have a better understanding of what is happening. All the things I have ever read/seen (been OC'ing a long time) is that if clocks go up, so does performance (I know, over simplified, but you know what I mean).

Thanks for your insight in advance!
 

Kckazdude

[H]ard|Gawd
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Seems I have run into this same problem with the same card as you. Cant say what the problem is. I know if I bump the OC up from when my performance drops I get artifacts or hard locks on 3D video. Drop it back down a bit and all performs as expected. It would seem that 350/750 is the happy spot for most BFG 6800 OC since that is where I see the majority at.
 

legcramp

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it's called a voltmod if u want stable higher clockspeeds to give better performance.. but insufficient cooling would not be nessesary... grr forgot how to spell nessesary lol
 

lithium726

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the card is getting too hot or it is failing nvidia's internal diagnostics (im guessing, i actually just made that up cause it makes sence, cuase it doesnt seem that hot) and the card is throtlling hte clock speed on the core down to keep hte card operational
 

lithium726

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lobstar said:
Thats the point though, lith, my stability is there, and its running nice and cool, but still lowering the performance. I thought volt mod would only help with stability and/or artifacting, neither of which I am having a problem with.
all i can say is that something is going wrong internally when the card is rendering the scene, my GT does this as well when i clock the core too high, and the card is nice and happy and loads at about 65c... also, that load temp seems really, really low... are you checking it right as you exit the game? if you are, you ight want to run rhdribl ( i know i spelled that wrong) and check the temps when it is on peak load, the core temp goes WAY down as soon as you exit 3D mode

edit: its rthdribl, and make sure you run it at as large a window as you can, itll heat up the GPU more the higher the res is
 

Kckazdude

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Actually, if you think about it, the throttling the core back makes some sense. The part that is hard to figure is at what temp does it decide to throttle back. While 58-60°C is hardly what I would call heating up, think I read somewhere that the 6800 was good to 90-100°C. It may be dependant on what BFG set it. Not sure if this is a BIOS issue or not but that should be where it is controled from. Another problem is I never hear my fans speed up except during boot up which would argue against this theory as well.
 

lobstar

Limp Gawd
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lithium726 said:
the card is getting too hot or it is failing nvidia's internal diagnostics (im guessing, i actually just made that up cause it makes sence, cuase it doesnt seem that hot) and the card is throtlling hte clock speed on the core down to keep hte card operational

In my testing on working up the clocks, I have noticed the heat increasing ever so little, but never going up, spiking, then going down. I do have the OC protection thing disabled so it doesnt tell me that the test failed for OC'ing. Does that mean its not actually applying the speed I am telling it to upto a point? The reason I ask is that those scores are pretty close (little higher) to the stock scores. Also, this is a gradual decrease in scores. going up from stock, and down from the sweet spot of 360/750. Is this throttling dynamic some how? Is there anyway to disable it?
 

lithium726

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yes, but we dont know if it is throtlelling becasue of heat, as i know mine was running cool enough, yet it still did it. every time it did, it would give a slight pause, a hitch in the gameplay like it was resetting itself, and the all the sudden my frames would take a nosedive. the only thing i can think of to explain this would be that the core calcuated soemthing wrong, caught itself, and throttled down to prevent crashing.

eidt: also, i really dont think 58c is his true load temp, the 6800GPU was made to take up to 120c on load, and most cards load at around 75-85, i have an NV5 on mine, and it keeps it much cooler than the stock did. (loading at 93 before, now its like 73)
 

lithium726

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lobstar said:
In my testing on working up the clocks, I have noticed the heat increasing ever so little, but never going up, spiking, then going down. I do have the OC protection thing disabled so it doesnt tell me that the test failed for OC'ing. Does that mean its not actually applying the speed I am telling it to upto a point? The reason I ask is that those scores are pretty close (little higher) to the stock scores. Also, this is a gradual decrease in scores. going up from stock, and down from the sweet spot of 360/750. Is this throttling dynamic some how? Is there anyway to disable it?
it doest spike, as soon as the 3d mode shuts off, te GPU goes back into 2d mode.. which means lower voltage and not being pushed at all. it can drop nearly 20c in just the time it takes your monitor to adjust resolutions and get your desktop back.

edit: there is no way to disable throtteling. you can do a voltmod on your card and it will alow higher overclocks, as long as the PCB can take the voltage you are pumping thorugh it. if you would like info on this, i can give it to you toamrrow, but right now, its 11 20, and i have an american politics essay final tomarrow, and i gotta get crackin on the studyin:)
 

lobstar

Limp Gawd
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I'll double check with that HDR proggy and see what she does. It may be my bad on the temp thing. Thanks for the info. I'll test Wedn night and check it. That may be the road to the reason!

EDIT** First test with that proggy is 65c. I'll run more later to find out what she is doing at each OC stage.
 

lithium726

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no prob:cool: glad i could help

if you want to try the voltage thing, its not a hardware mod like on ATi cards, you modify your stock BIOS to give more voltage to the core and reflash the card with the modified bios... and since you are flashing it with the bios that came with the acrd, only slightly modified, its pretty risk free, but i accept no responsibility for damages:p

ok, now i REALLY gotta study..
 

peacetilence

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I said it in another thread and I'll say it again

Problems with these cards aren't related to heat. Heat isn't even what kills these cards when you overclock. You'll be lucky to get 400/1100 and not notice artifacts when more games come out that push these cards. If I were you I'd settle on a lower overclock right now and be happy with it. 385/1100 seems to be the best at the moment. You could always flash your card to 1.4V but it will probably die within 2-4 months.
 
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