Overvolting 6800 GT pitfalls and outcome

Demolisher

Last night, after realizing that I am going no further than 415/1.06 with stock cooling, I decided to give overvolting a shot. I backup up my BIOS and loaded up NiBitor.

It showed my volatges as:

1.4 v (3D?)
1.3 v (2D?)
1.1 v (Throttling?)

So, based on forum reading I changed them to 1.4 v / 1.4 v / 1.4 v in short order, burned the BIOS back and rebooted. To my surprise, the RAM became more overclockable, allowing me to go beyond 1.1 GHz. However, the GPU went in the other direction. 3dmark05 would crash on all GPU speed settings down to 400 MHz, at which point I stopped trying and decided this just isn't going to work out. I tried again with 1.4/1.4/1.1, just for grins, which fixed absolutely nothing from the all 1.4 settings. Finally, before calling it quits and reverting the BIOS to the original, I decided to try what most people wouldn't even consider.

I changed it to 1.3/1.3/1.1 . What the heck, I thought. Undervolting it wasn't going to hurt it, so why not see what it does for me. To my surprise, the RAM became slightly more overclockable, without artifacts, than at the stock 1.4/1.3/1.1. I was able to go from 1.6 with stock, to 1.96, before I could no longer pass the driver test. Also, since I was running at 1.3 v in 3D, the temperatures were slightly lower under load. The GPU did no worse than with the base BIOS settings, allowing me to stay at a cumfy 415 MHz. So, in the end 415/1.96 was possible, giving me a boost in 3dmark05 from 5093 to 5164.

Conclusions:

1. I have a heat problem. There's no doubt about it. With an idle of 60-61 and load temps between 80 and 85, at stock voltage, overvolting just isn't making matters any better. I think I'll have to just stay at undervolting until I put better cooling on the card (i.e. NV5 Silencer), which I am hesitent to do, since I will break warranty. I'll leave the NV5 for when I'm absolutely sure the card is good and has no hidden short term faults (e.g. a month from now).

2. I am surprised that undervolting could possibly have made the RAM run higher. Also, I just don't understand why overvolting makes any difference if the 3d is already at 1.4v to start. But, as can be seen from testing, it does make a difference when you go all 1.4v, which boggles my mind. This is especially true since my GPU crashes were not in the transition from 2D to 3D, but at some later point during the test, at which point the card has been running at 1.4v stock for a while and the 2D voltage should have no bearing. I just don't get why this is a factor.

Please post comments about your experiences.

Thanks,

Demolisher

MiDKnYtE

Sounds like you are using nibitor v1.7.
http://www.mvktech.net/content/view/193/37

Try running v1.6a to see the difference. 1.1v is 2D and 1.3v is 3D.

the only value you need to change is the green 1.3v value (voltage ID) to 1.4v.
basically, your card will be looking to use the 1.3v VID, but will produce 1.4v instead.

1.3v is the normal voltage on a GT core, so you're not underclocking.

60 is on the high side to idle. mines usually idles in the mid 50s.

Shike

Frankly I used the old Omniedit and it did great for my card ^_^

When I tried to hit Ultra on RAM, it was a no go and throttled at 425.

The fix? Don't touch the freakin 2D voltage and just popped the throttling voltage to 1.4v

After this I hit 425/1.1ghz on stock cooling no artifacts whatsoever.

Also, if you put throttling at 1.1v by how you organized your post, I bet it was killing the OC off...just a thought

MiDKnYtE

Nibitor is the newer version of Omniedit. They made a major change in version 1.7. Please read the link I posted for more details.

Shike

Please try to deal with your literacy issues, I wrote:
I just know Omniedit worked well with mine, and that's all I was saying. Also aren't you using an EVGA copper cooling solution and not comparing it against stock?

60 is just fine, don't worry about him.

MiDKnYtE

No I was comparing to when I had the aluminum heatsink. with the copper it idles in the lower 50s. It depends on where he is, so the ambient temp might just be higher there, but it's just an observation.

I'm just saying they changed omniedit for a reason, but you can use whatever you want. no need to get defensive.

wow you guys take stuff so personal. geez.

Shike

Yes, I do take stuff personally....

MiDKnYtE

I'm just trying to help you guys out. You can take my advice or you can ignore it. I'm not perfect, nor do I claim to be. Let's just agree to disagree.

IceRedwing51

415mhz Core / 1.96GHz Memory? the memory can't even go past 1.4 on coolbits