Palit GeForce GTX 680 JetStream review - Overclocking the graphics card

Overclocking the graphics card

As most of you know, with most video cards 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 to 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 AfterBurner which will work with 90% of the graphics cards out there. We can really recommend it, 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, to not 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 push the frequency often 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 will 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 with the Dynamic boost function of the series 600 cards overclocking is definitely going to be more complicated. It remains simple though. Mind you that for overclocking we used Beta 15 of AfterBurner for ease of use.

In Afterburner or the overclock tool of your preference we go into the preferences. We can widen up the TDP limitations a bit, set the power limiter towards it's maximum. That way the Dynamic boost function won't down clock all the time to meet it's upper threshold in TDP limitations.

We have core voltage upped another 100Mv, but the NVIDIA driver currently does not seem to kick in the additional voltage.

The Core clock was increased with another 100 MHz we tried higher yet got some instability and our overclocks and tweaks are always based 100% game stability.

The memory on this board is flying frickin fast! We got it running stable at 3600 MHz, which is a 7200 MHz effective gDDR5 datarate.

So for the core we ended at roughly 1250 MHz with the dynamic clock kicking in, absolutely stable and for the memory we ended at 7200 MHz (effective data rate). At this stage we locked the cooler RPM at 65% RPM, that's on the high side and now audible but it keeps the GPU under 55 Degres C (!). With that extra performance at our hands, have a peek at the results when overclocked.

Above, Crysis 2, same maxed out image quality settings as before yet now with added overclock results:

• DirectX 11
• High Resolution Texture Pack
• Ultra Quality settings
• 4x AA
• Level - Times Square (2 minute custom time demo)

Above, 3DMark 11 - the Performance test and score. As you can see, there is an additional bump in this very GPU intensive software, lovely.

Above, Alien versus Predator, in 1920x1200 at 4xAA and 16X anisotropic filtering