GeForce GTX 580 SLI review

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Overclocking the two cards setup in SLI

 

Overclocking the two cards setup in SLI

As most of you know, with most videocards you can apply a simple series of tricks to boost the overall performance a little. You can do this at two levels, namely tweaking by enabling registry or BIOS hacks, or very simply tamper with Image Quality. And then there is overclocking, which will give you the best possible results by far.

What do we need?One of the best tools for overclocking NVIDIA and ATI videocards is our own Rivatuner that you can download here. If you own an ATI or NVIDIA graphics card then the manufacturer actually has some very nice built in options for you that can be found in the display driver properties. Based on Rivatuner you can alternatively use MSI AfterBurner which will work with 90% of the graphics cards out there. We can recommend it very much, download here.

Where should we go?
Overclocking: By increasing the frequency of the videocard's memory and GPU, we can make the videocard increase its calculation clock cycles per second. It sounds hard, but it really can be done in less than a few minutes. I always tend to recommend to novice users and beginners, not to increase the frequency any higher than 5% on the core and memory clock. Example: If your card runs at 600 MHz (which is pretty common these days) then I suggest that you don't increase the frequency any higher than 30 to 50 MHz.

More advanced users often push the frequency way higher. Usually when your 3D graphics start to show artifacts such as white dots ("snow"), you should back down 10-15 MHz and leave it at that. Usually when you are overclocking too hard, it'll start to show artifacts, empty polygons or it may even freeze. Carefully find that limit and then back down at least 20 MHz from the moment you notice an artifact. Look carefully and observe well. I really wouldn't know why you need to overclock today's tested card anyway, but we'll still show it.

All in all... do it at your own risk.

Now this was not really surprising, but as you can see, the card can overclock much MUCH higher and that has a very positive effect on overall performance. At default you'll easily lift the card over 800 MHz on the core.

Original This sample Overclocked
Core Clock: 772MHz Core Clock: 772MHz Core Clock: 850MHz
Shader Clock: 772MHz Shader Clock:772MHz Shader Clock: 1700MHz
Memory Clock: 4000MHz Memory Clock: 4000MHz Memory Clock: 4400MHz

Now we left fan RPM control at default in all circumstances. Temps on one of the cards go up to 90 Degrees C on the GPU, that is still fine ... but borderline. We would not recommend any voltage tweaking at this pont. So let's have a look at some examples while overclocked.

COD: Modern Warfare 2, maxed out quality settings as before with 4xAA 16xAF

All the way down a single GTX 580, then the middle blue line the SLI setup and then overclocked on both GPUs to 850 MHz core and 4400 (effective datarate) on the memory.

When you have so much brute horsepower already, it really becomes difficult to show any real gains in performance with overclocking. Perhaps with a more GPU bound title that will show better, let's check it out.

Battlefield BC2, maxed out quality settings, same as before with 8xAA 16xAF

If you look at 1280x1024 to say 1600x1200 you'll notice that normal results and overclocked results are very close to each other ... that's the CPU bottlenecking the GPUs and thus it can not feed the two graphics processors enough data fast enough. After that resolution the GPU overclock starts to show again.

And yes 3DMark Vantage benefits as well. We reach a 40k GPU score and 34K for the overall P score, quite nice but again, the processor is now holding back the overall P score.

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