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View Full Version : How do you all manage such solid overclocks with your 6800gt's???


GRAFiZ
02-15-05, 02:34 PM
I run two BFG 6800GT's in SLI, and cant get more then 390/1040 stable overclock.

It just seems odd to me that I'd get such a dud card(s).

I used to have a BFG 6800 Ultra AGP as well and could only get around 440/1150 stable on that as well.

I'm using solid parts, my PSU is the PCP&C 510SLI, my 12v line i solid at 11.9v under load, I've got plenty of 120mm case fans.

What should I do?

I'm a bit afraid of killing my warranty with any soft of modifications, but would removing the heatinks and applying Arctic Silver 5 to the core and ram help? Or maybe adding an NV5 heatink or simular?

Is it hard to do such a thing and would BFG void my warranty?

Thanks!!!

|MaguS|
02-15-05, 02:41 PM
You probably got a bad batch, AS5 wouldn't help really and a NV5 would abit but on SLI it would be bulky (would it even work?). I would just leave it, 390/1040 is nothing bad at all, its still a great OC.

ViN86
02-15-05, 02:51 PM
maybe a problem with voltage and your PSU? i mean, a 6800GT SLI setup will suck a lot of power compared to one 6800GT. ;)

J-Mag
02-15-05, 03:04 PM
Have you tested both cards individually beforehand? If you get one good one and one bad one, then they will obvisouly only overlcok to the maximum of the bad one's speed.

I have two BFG 6800GT's and so far the best I have got them up to before the tests fail in the coolbits enable driver screen is 417core 1130mem.

Initially, I had just one card and it would clock at 422core 1200mem.
When I got my second card, I took out the original and tested it by itself and was able to push 425core 1180mem.

So even with the lowest of both I should have 422 1180, but thats not the case. I think that even if both you cards performed exactly the same they till wouldn't OC as good together. I mean there are obviously more points-of-failure in an SLI setup as the cards have to talk together and an error that normally wouldn't even exist is now possible...

As a side note I am using a 400w Zippy and under load w/ one card minum is 11.99 but under load with two cards I can see a drop down to 11.95 (measure with multimeter). These two figures are well within Specs, but I wonder if more power would help me out...

$n][pErMan
02-15-05, 04:13 PM
As a side note I am using a 400w Zippy and under load w/ one card minum is 11.99 but under load with two cards I can see a drop down to 11.95 (measure with multimeter). These two figures are well within Specs, but I wonder if more power would help me out...
Mine drops to 11.83v if I have the fans running on full on my video card and burn a DVD at the same time .. lol. I think my 12v rail is under stress :p

NemesisChild
02-15-05, 05:35 PM
I run two BFG 6800GT's in SLI, and cant get more then 390/1040 stable overclock.

It just seems odd to me that I'd get such a dud card(s).

I used to have a BFG 6800 Ultra AGP as well and could only get around 440/1150 stable on that as well.

I'm using solid parts, my PSU is the PCP&C 510SLI, my 12v line i solid at 11.9v under load, I've got plenty of 120mm case fans.

What should I do?

I'm a bit afraid of killing my warranty with any soft of modifications, but would removing the heatinks and applying Arctic Silver 5 to the core and ram help? Or maybe adding an NV5 heatink or simular?

Is it hard to do such a thing and would BFG void my warranty?

Thanks!!!

How many amps are running on your +12v rail?
As you mentioned, I wouldn't recommend any soft mods.
If you have problems, you could fry two GT's (ouch!!!).
Oc'ing a card is strictly "luck of the draw".
However, you should be able to successfully OC at Ultra frequencies (400/1100).

GRAFiZ
02-15-05, 05:49 PM
How many amps are running on your +12v rail?
As you mentioned, I wouldn't recommend any soft mods.
If you have problems, you could fry two GT's (ouch!!!).
Oc'ing a card is strictly "luck of the draw".
However, you should be able to successfully OC at Ultra frequencies (400/1100).

I'm using a Power PC and Cooling 510SLI.

Well respected and thought of to be the best power supply on the market today. 12v brings in between 34 and 38 amps.

Yeah, I'm not looking at any real mods, I was just wondering about third party cooling, thats all. However, I will not modify the hardware at all if it jeapordizes my warranty. BFG gives me a lifetime warranty, if I ever have to use it I dont want any problems.

I cant hit Ultra with it at all, thats why I was asking. Seems most everyone I know of who has these BFG PCI-E 6800GT's hit ultra speeds without any troubles.

I'm running in SLI mode which is known to hurt overclocks a little.

Anyhow, was just looking for ideas, thanks much all. :cool:

john19055
02-16-05, 12:23 AM
No aftermarket cooler is going to get you enough of a improvement to be worth it,unless you go with water or something more extreme.And like you said a SLI setup is not going to overclock as good as a single card would.Power PC & Cooling is a great power supply but we are taking about a video card that sucks power and haveing two of them plus all your other things that use the power supply it just can go so far and I have heard that the SLI setups excepicaly the 6800 Gt and ultra have been eating power supplies for lunch even the Power PC & Cooling ones,IMO I would be happy at 390 but I only have one card.

MustangSVT
02-16-05, 12:24 AM
The best power supply is the PC Power and Cooling 850W. It costs around $430.

Oh and no power supply is going to increase your overclock. It's luck of the draw. If you're not satisfied, then tough luck. Nobody guarantees overclocks. How are we getting such good overclocks? Not that many people run BFG 6800 GT's PCI-E in SLI. If it can't hit it on your setup, then that's it and you'll have to deal with it.. What I did for example was buy a 6800 GT that's guaranteed Ultra clocks (400/1100) out of the factory and covered by warranty. Besides, nobody's setup is the same.

GRAFiZ
02-16-05, 01:07 AM
The best power supply is the PC Power and Cooling 850W. It costs around $430.

Oh and no power supply is going to increase your overclock. It's luck of the draw. If you're not satisfied, then tough luck. Nobody guarantees overclocks. How are we getting such good overclocks? Not that many people run BFG 6800 GT's PCI-E in SLI. If it can't hit it on your setup, then that's it and you'll have to deal with it.. What I did for example was buy a 6800 GT that's guaranteed Ultra clocks (400/1100) out of the factory and covered by warranty. Besides, nobody's setup is the same.

Uhh, you're wrong. First off, the 850watt model isnt even for sale yet, I'm talking about products you can actually own, secondly, it will not be a very good choice for the home user as it will feature 4 12v rails, totalling 60amps, but while probably not providing more then 15 amps on any single rail.

That type of power supply design will not be able to give your mobo, cpu and video cards the required amperage.

The new 850 is being designed for servers using 2 or more CPUs. Call them up, they'll tell you NOT to buy it if you're going to just be running a single cpu system.

Also, a power supply CAN and WILL effect your overclock, without enough power, specifically amperage on your 12v rail, you WILL exerpience stability issues at higher overclocks.

Finally, I never said it wasnt my "tough luck". I was only asking for suggestions, I have read your post a few times and get a feeling that you're being a bit short with me. I am hoping it's all just a miscommunication.

ChrisRay
02-16-05, 01:13 AM
Well certainly SLI setups dont get as high of overclocks as single setups. I have already encountered this problem.

jAkUp
02-16-05, 01:25 AM
I have not tried OC'ing, but how are your temps?

NV5 Silencer should help, especially on GT's. I got 20 more mhz out of my 6800 ultra AGP with it.

GRAFiZ
02-16-05, 01:32 AM
I have not tried OC'ing, but how are your temps?

NV5 Silencer should help, especially on GT's. I got 20 more mhz out of my 6800 ultra AGP with it.

Depends on my drivers, below 70.XX idle low 50's, load mid 60's.

Above 70.XX idle mid 60's, load low 70's.

Golden Boy
02-16-05, 02:34 AM
I don`t know... but isn`t running 2 "standard" 6800GT`s in SLI already enough power for todays games ?

Sure overclocking is nice for some better benchmark scores, but i don`t think you will miss that 20-30Mhz more in most games.

I would be happy if i just had SLI and if it would work without problems !

just my 2 cents

GRAFiZ
02-16-05, 02:40 AM
I don`t know... but isn`t running 2 "standard" 6800GT`s in SLI already enough power for todays games ?

Sure overclocking is nice for some better benchmark scores, but i don`t think you will miss that 20-30Mhz more in most games.

I would be happy if i just had SLI and if it would work without problems !

just my 2 cents

LOL... thats what everyone says, but look at it this way, there are VERY many people who would ask that question of someone even running a single 6800GT. As with all things in life, it's relative.

Also, not all games utilize SLI, in fact, it's very primitive and quite buggy. Because of that, I have to play many games using just one card, so, at high resolutions, it helps quite a lot.

Marcos
02-16-05, 07:47 AM
I went from a 350w 16 or 18a rail ( i dont remember) I was getting 420/1.11
I changed to the 500w w/ a 34a rail and Its not stable when I over clock 400/1100 like wtf scoob??

I can do 400/1000 still, but who cares so i keep it stock for now

PSYCHODAD
02-16-05, 11:41 AM
I run my 2 XFX @370/1020. Tried overclocking to 400/1100, but got arties in 3Dmark05.

Most of the difficulties I've encountered with my system were corrected with the Nhancer profile editor btw. No more bugs that I'm aware of. :o

Marcos
02-16-05, 08:33 PM
ugh i couldnt oc because of the drivers i had, i got the 71.25 and im yealding massive overclocks

Salamandar
02-16-05, 08:54 PM
My Gigabyte with Nv5 works great @ 430/1170, I didn't try any higher because my system is holding me back.

fugu_fish
02-17-05, 08:15 AM
Uhh, you're wrong. First off, the 850watt model isnt even for sale yet, I'm talking about products you can actually own, secondly, it will not be a very good choice for the home user as it will feature 4 12v rails, totalling 60amps, but while probably not providing more then 15 amps on any single rail.


You're wrong, too. You assume that you will run everything from one 15A 12V rail. My NeoPower 480W has 2 12V rails, one 18A and one 15A.
I run the motherboard off one and my video card, fans and drives off the other.
Plenty of juice. Works great.

GRAFiZ
02-17-05, 11:14 AM
You're wrong, too. You assume that you will run everything from one 15A 12V rail. My NeoPower 480W has 2 12V rails, one 18A and one 15A.
I run the motherboard off one and my video card, fans and drives off the other.
Plenty of juice. Works great.

It totally depends on how the power supply is designed. Your power supply pumps the 15amp rail through the secondary 4-pin 12v plug on your motherbard. Then the 18amps get pumped through the remaining molex connectors.

This of course does work fine in certain situations, however, plenty of reports out there of SLI systems having problems with such power supplys because for instance, 15amps is plenty to give to your motherboard, the 18amps is not enough to give two 6800 GT's or Ultras, all while giving amps to raid drives, optical drives, etc.

Take a look around on line, more people have reported best results using a single high amperage 12v rail, then two seperate lower aperage rails.

This will be the possible problem with the new 850watt PSU, and why they tell you not to buy it if you're just using a single CPU.

One of the 12v rails will go through the 4-pin ATX, then another 12v rail will go through an additional 8-pin connector, that as of now will only work on dual CPU mobos.

IF, they run both remaining 12v rails through the additional PCI-E and molex connectors it will only give you two 15amp rails to work with. Unless it's balanced well, you might see only 15amps through both PCI-E connectors. Many argue that simply will not be enough.

All in all... dual or more rails can work in most situaions, but talk to electrical engineers, they will tell you higher amperage through one line is better then less through several.

Let me add I have three 24pin ATX PSU's for my testing.

A Vantec 520A Stealth - 26amps on a single 12v.

A BFG 550 watt PSU (Rebadged Fortron 550) Dual 18amp 12v rails.

A PCP&C 510SLI - 34/38 amps on the 12v rail.

On my system, the one in my sig, using a pretty high priced multimeter I recorded these results:

Vantec 520A - idle: 11.9v - load: 11.4v

BFG - rail 1 - idle: 12v - load: 11.6v : rail 2 idle: 11.7v load: 11.4v

PCP&C 510SLI - idle: 12.15v - load: 11.96v

Idle is sitting in windows, fully overclocked.

Load was during 3d mark 2005 loops and S&M CPU/FPU testing, as well as Prime.

Results speak for themselves. Since putting in the PCP&C I have achieved a much more stable system. I am able to benchmark longer and run Prime for hours longer then with the other PSU's.