Overclocking and Conclusions
Additional Overclocking Results

So it should go without saying that just flipping the switch on the HD 6990 into “overclocking” mode will get you some improved gaming results, the real benefit is that it opens up the card to even more overclocking potential with a slightly higher voltage and higher wattage allowances for PowerTune.  Here is what I said in my first HD 6990 write up:

AMD is definitely letting the enthusiast users have their way with the HD 6990 as even in the Overdrive settings in the control panel you will have the option of pushing the boundaries of the 3000+ stream processors even further.  The software will allow clock speed settings as high as 1.2 GHz, a 44% increase over the reference speed, though of course they aren’t going to be promising you will get there.  You will remember that previous iterations of Overdrive on single GPU boards limited the overclocking potential to 1.0 GHz and it actually limited us in our attempts on several occasions. 

So how much performance could we push out of this card?  Here is the maximum frequency I was able to reach with stable results:

AMD Radeon HD 6990 4GB Update - Overclocking Performance - Graphics Cards  1

Despite my best efforts I could not get above the 950 MHz frequency without running into a situation with system crashing and blue screens.  So while even though the slider bar can hit 1200 MHz, our sample came no where close to that.  At 950 MHz we did see scaling in performance as we would have expected it adding another 5% or so to the GPU-limited games over the 880 MHz standard overclocked setting.  If we compare this 950 MHz setting to the 830 MHz reference speed though, it does look a look more interesting with a 14% clock rate increase. 

In general, users that get the Radeon HD 6990 4GB card will have to decide if the performance improvements are worth the added power consumption and potential sound level increases that go along with it. 

Is the extra power worth it?

In order to meet the requirements of system builders across the globe, AMD had to make the default configuration of the Radeon HD 6990 to fit in the <375 watt window.  But having spent a good amount of engineering making this card capable of much more, AMD wanted to be sure they could offer the full feature set and flexibility to the consumers that could utilize it.  You will notice that as soon as we flip that advanced user switch the power consumption rocketed up a good 60 watts moving us into the 425+ watt consumption for a single graphics card. 

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I think for most GAMERS, the stock settings on the HD 6990 are going to be enough and if you are willing to shell out the $700 for it, then you are going to be more than happy with what AMD was able to create for you in its default state. 

Flexibility for Extreme Overclockers

I think the real target audience for the advanced user switch, voltage increase and PowerTune adjustments is not the gamer wanting to get the most of their investment but rather the extreme overclocking nut that uses LN2 to break records and set the PC world on fire (sometimes literally).  While we were only able to hit the 950 MHz mark with the reference cooler installed, people interested in getting past the 1000 MHz mark and maybe into the 1100 MHz territory will likely be able to do so with a little liquid nitrogen and some more voltage modifications. 

AMD assures us the PCB is built for just that purpose so we are interested to see how long it will take to get these cards into the record books. 

Final Thoughts

I am glad to see AMD really embracing the overclocking mindset in both its CPU and GPU divisions as well.  AMD has been offering unlocked processors for quite some time and with previous Radeon releases and now the new HD 6990 offering, the engineering and marketing teams continue to strive to beat out the competition in anyway they can.  By installing a switch on the card that now basically overclocks the clock speeds and moves the power consumption beyond approved levels, AMD is enabling consumers that WANT to push their hardware the option to do so, and for that, we at PC Perspective are very grateful.

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However, after playing with the overclocking options on this card, for the average consumer I don’t think much changes from our conclusion last week.  Oneu might think it odd to consider anyone that buys a $700 video card an “average consumer” but I think there remains a gap between a “gamer” and an “overclocker” and the Radeon HD 6990 4GB card offers up enough for both.  The overclockers get a lot of switches to tinker with and the gamers, well they get the fastest graphics cards on the planet. 


Further Reading

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