Max safe voltage on 6800GT

**ic3m4n2005** · 08-20-2005, 04:43 AM

As the title says, i've got a 6800GT PCIe and bought a watercooler for it. SO i will try a Bios mod. 1,3v is stock isn't it ? So what would you consider as safe voltage for 24/7 usage ?

**Reflex1** · 08-20-2005, 03:21 PM

1.4v ...a lot of people have tried 1.4v without problems, dont go higher for 24/7.

some say the increase of volts doesnt help, but some say it helps so just try and see if it works for out you.

**ic3m4n2005** · 08-20-2005, 03:55 PM

ty will try, what about the rams ? Is it possible to do a softmod too ? Rams will be watercooled too.

**alexio** · 08-20-2005, 04:00 PM

I think 1.5v for 24/7 use is safe, even 1.6v is not very dangerous with watercooling. Just remember that the same cores at a 6800U card have to run 1.4v 400mhz 24/7 with the most crappy cooling solutions ever. They are running at 85 *C fairly often.

I don't know about the RAM.

**Jochenp** · 08-27-2005, 12:22 AM

At this moment ramvoltage isn't adjusted by the bios, so you can't change it without your soldering iron.

**D3kMatrix** · 08-29-2005, 08:58 PM

I modded my 6800GT bios to 1.4v, and my load temps only went up like 2c (was probably ambent temp more then anything)

And it has a Zalman VF700cu HS btw.

Max load temps I've seen on this card with the zalman is about 60c, and thats at 405/1105 w/ 1.4v

**MrSeanKon** · 08-30-2005, 03:38 AM

1.5Volts for 24/7 are safe anyway you can use 1.6V cos of w/c

but I don't suggest you more.

**ic3m4n2005** · 08-30-2005, 03:03 PM

I've got wc on the card now, temps are 45 idle and near 60 load on stock clocks. The temps don`t change more as 1-2 degrees if overclocked or not. Will try bios mod now, wish me luck

**NickS** · 08-30-2005, 03:14 PM

1.5 Max definentally.

1.6 is way to high even for phase change or something like that if you're gonna be going taht extreme for cooling :O

**Postal Dude** · 09-13-2005, 03:58 AM

I Thought that 1.4 and definately 1.5 would kill the power managment on the card?

**MikalCarbine** · 10-02-2005, 06:47 PM

What if you properly cool the power management? ie: the mosfest and regulators

**Postal Dude** · 10-02-2005, 06:52 PM

I dunno about anyone elses experiences here. Im sure that improved cooling on them will help reduce the effects. But think about it before you mod it. Can you afford to replace the card? Im running a 5200, 64bit!!! because my gt died from a vmod. Not poof not working. Jus slowly dying, it wont even run at stock.

**MikalCarbine** · 10-02-2005, 06:55 PM

Well I will let you all know when I mod my card this coming week.

I do have some money in my bank account if it does die, I'll pick up a 7800gt or one of them new ATI's (whichever is more sexy)

I need better cooling, my NV5 is crap.. I was running at 440/1130 but it heats up so much that I artifact all over the place. Then I was running at 430/1100 but FEAR heats that baby up to 80C!!!

I ordered a Zalman Vf700-cu, but I've heard they are either hit or miss in temps... we shall see..

**MikalCarbine** · 10-13-2005, 06:21 AM

Got the VF700-Cu last week, it's pretty damn nice.

Idle temps are 49 (with normal room temp) and 46 with it being cold out nowadays. Load is around 63, and that is with my 441/1151 clock

How much could I expect the temps to rise if I upped the vgpu to 1.4?

I am going to take off the heatsink on the power regs and put some AS5 on them, then rig a fan onto em, that is if I do the vmod

**revenant** · 10-16-2005, 05:25 PM

It's not the core which will get strained at 1.4v, it's the MOSFETs, or the lack there of on a 6800GT, it's missing one so the other four will have to work extra hard with the higher voltage... the core is good with proper cooling to 1.5v or maybe even 1.6 (on water)... but it's the power regulators which will take the biggest hit there.. make sure you have a lot of air on the MOSFET sinks when vmodding like this..

**MikalCarbine** · 10-16-2005, 05:27 PM

The stock cooler on the mosfets, is that legit? Or should I replace it/mod with AS5?

**Touche Turtle** · 10-21-2005, 01:59 AM

I replaced the white thermal pads on my 6800GT's mosfets with AS5 and noticed that the 'sink no longer made contact with the components it was cooling :o - the heatsink was designed to take the thickness of the pads into account. I had to sand the 'sink's "feet" down a mil or 2 before proper contact was made between the top of the components and the base of the sink.

This may not be the case for all 6800GTs but it's definately worth checking if you plan on using a heat transfer compound on you GTs mosfets.

**MikalCarbine** · 10-22-2005, 09:45 AM

I was curious if that'd happen.

Did you mount a fan on the mosfets at all?

**Touche Turtle** · 10-24-2005, 01:43 PM

Not yet but I probably will before trying 1.5v, just incase.

**MikalCarbine** · 10-24-2005, 01:45 PM

I just finished modding the mosfet stock cooler (put as5 on it, sanded down the ends of the hs with my dremel) and mounted an 80mm right by it blowing on em. I am going to sink the little V150 448 chips soon too, I am glueing together some mosfet heatsinks with thermal expoxy to make one big sink.

I will be going 1.4v tonight hopefully

Edit:
Just went 1.4, real voltage is 1.43 idle 1.45 load, idle temp went up 1C (now 49C) and Load 3C (67C)

Looking good, lets see if I get any more clock speed

Edit2: Seems my max now is 462 1.4v, from 441 1.3v (1.35real)

Now my question is, is that small increase worth the chance of killing the card?

**Touche Turtle** · 10-26-2005, 06:50 AM

Nice overclock!

I'm very surprised that 1.4v has killed so many cards. I've had my 6800GT for 18mnths now (it's an early card which probably explains why it wont overclock as far as many others) and have had it running at 1.4v for over a year with no problem.

The V150 448 chips you mention - are they the 3 components running alongside the GPU-side of the thin heatsink? I have 3 components there too but on my card 2 are "V100 412" and 1 is "S200 413". Strange!

**MikalCarbine** · 10-26-2005, 01:35 PM

There are three of the V100 and one V150 very interesting how you have a S200 413, I wonder if it is a higher quality or a higher phase power manager?

Edit:

BTW what brand 6800gt? PCIe?

What mods have you done to cool that bad larry?

**Touche Turtle** · 10-27-2005, 01:30 PM

It's an Inno3d AGP card picked up in Honk Kong. Not the most recognised brand in Europe but it was a bargain at the time.

There are no mods except the 1.4v bios mod, the sanded feet on the thin heatsink and AS5 all-round. The card is cooled by an Arctic Cooler NV5.

**MikalCarbine** · 10-27-2005, 02:07 PM

Interesting! No air blowing on the power regs? the NVS5 seems to cover it up, heat must build up

**Touche Turtle** · 10-28-2005, 01:57 AM

I don't think 1.4v is that much to worry about. Can't be too careful though, I suppose.

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