Overclocking Gigabyte GV-N56GOC-1GI graphics cards in SLI configuration?

[Mr Davo]

Hi Everyone,

I have two Gigabyte GV-N56GOC-1GI (GIGABYTE - Graphics Card - NVIDIA - PCI Express Solution - GeForce 500 Series - GV-N56GOC-1GI) graphics card in SLI configuration, and a few questions to ask the forum community -

1). What is a safe operating temperature for these cards? Typically they run between 42 to 50 Degrees Celsius when not overclocked. However I have started to experiment with overclocking and had them sitting between 55 - 60 Degrees C.


2). GPU to Memory Bus ratio: I have divided the Memory Bus frequency by the GPU frequency (the end result being approximately 4.2), and then when overclocking have simply nominated a new GPU frequency (of say +100MHz over default) and then calculated a new memory bus frequency using the ratio. Is this a good approach to overclocking the frequency on these cards?


3). I have been using the Gigabyte Overclock Guru II software, however I am wondering if I can get away with using MSI AfterBurner with my cards?


Any help here will be much appreciated.


Kind Regards,


David

[profJim]

Re: Overclocking Gigabyte GV-N56GOC-1GI graphics cards in SLI configuration?

Do a web search using: "gtx 560" overclock guide (with the quotes) and watch the related youtube videos and read several of the overclocking guides. If you've already read some of the detailed web reviews for your video card, you should have a pretty good idea how high you can probably overclock your gpu and memory speeds. If you have below average cards, your o/c will be somewhat lower and above average cards can probably o/c higher.

The o/c settings in the GTX 560 Ti reviews, guides or videos won't directly apply to your video card.

My basic overclocking procedure is to increase the gpu speed in a small increment and then stress test this setting. If you get screen artifacts, the video driver crashes or you get a system error, then you increase the gpu voltage by 1 click and repeat the stress test. With my video cards, MSI AfterBurner had a safe fixed maximum voltage that I could use.

If AfterBurner will let you increase gpu and memory voltages, you're good to go.

You can download MSI AfterBurner and its user manual at MSI Afterburner
Avoid the latest beta versions because the beta's all have a final expiration date.

note: I've never heard of using or applying a "GPU to Memory Bus ratio" with video card overclocking.

Overclocking memory is done differently because when your gpu drivers/software detect memory errors, your memory will automatically be down-clocked and you won't notice anything unless you look closely at stress test benchmark scores. Once you notice a consistently lower score, you need to lower your memory speed to the highest previous stable setting and retest again to make sure that the slightly lower memory settings are still stable.

With my GTX 460 video cards, my gpu speeds went from 790MHz (stock) to about 850MHz using stock gpu voltage settings. Going higher required increasing gpu voltage slightly until I maxed out the gpu voltage at ~ 915MHz. Many of my stress tests were stable up to 925MHz, but the Unigine Heaven benchmark often locked up or crashed above 915MHz.

I found that increasing memory speeds had much less effect than increasing gpu speeds. YMMV

My overclocked idle temps were about 30^o(C) at idle and usually in the 50^o - low 60^o(C) range when running video benchmarks. My case has excellent air flow and cooling with 20^o(C) ambient temperatures.

Here is the basic procedure that I used to overclock my GTX 460 SLI video cards:

load your highest stable gpu profile
:START
increase gpu speed by 25MHz
apply new gpu speed setting
test for artifacts by running FURMARK or KOMBUSTOR for 15 - 20 minutes
are there any screen artifacts?
-- if there artifacts, goto :HELL
goto :START

:HELL
increase gpu voltage by 1 tick
could you increase the gpu voltage?
-- if you can't increase the gpu voltage any higher, goto :DONE
save your current overclocked gpu settings as a profile
goto :START

:DONE
note: you've maxed out your gpu speed and your most recently saved gpu profile is the best that your can do.

It's been a long day and I'm not very proud of my gpu overclocking DO-loop.

[Mr Davo]

Re: Overclocking Gigabyte GV-N56GOC-1GI graphics cards in SLI configuration?

Hi profJim,

Thanks very much for your detailed response. I will take everything onboard, and look forward to using your overclocking technique.

Kind Regards,

Davo