The ASUS GTX 580, Final Clock Speeds & "OCP Removal"
The ASUS GTX 580
The ASUS GTX 580 Voltage Tweak is simply a reference GTX 580 with a few stickers on it. It maintains the exact same design as the original NVIDIA card we reviewed last week but its BIOS has been modified slightly for compatibility with ASUS’ SmartDoctor overclocking utility.
Even though this particular card can be pushed to extremely high levels when paired up with the Voltage Tweak ability, ASUS has decided to keep the standard 6-pin and 8-pin power connector layout and fan design.
Overclocking the ASUS Voltage Tweak Edition
After using a trio of GTX 580 cards for the last two weeks, we can honestly say that NVIDIA has released an overclocker-friendly card. Every one of our samples reaches between 875 and 902Mhz without any additional voltage or changes to the default fan speed profile. Memory overclocks also ranged from 1080 to 1150Mhz which is an excellent improvement over the stock 1000Mhz speed.
Using the included SmartDoctor utility, the ASUS GTX 580 nailed 888Mhz core speed without so much as an issue but going above that required a bump in voltage. Its memory meanwhile reached a respectable 1097Mhz or 4388Mhz QDR before the GDDR5’s error correction routines we mentioned in a past article kicked in and performance couldn’t be increased any more.
Something else we wanted to mention very quickly is that the core on ASUS’ “reference” GTX 580 is overclocked by 10Mhz from the factor. In essence, this gives you a “free” performance increase even though such a minor overclock will have next to no impact upon real world gaming performance.
These numbers are very good considering the stock clock speeds of the GTX580 but what we are really after in this article is performance at the highest clock speeds reachable under air with the fan operating at reasonable speeds. For that, we will need to increase voltage a bit…
By pumping the voltage to a moderate 1.138V we were able to push the core to 951Mhz which is a massive 179Mhz over the reference clock speeds. This was attained with a constant fan speed of 67% which is still quiet enough to not be noticed above the din of gaming.
We could have gone higher but we found this core clock / voltage combination offered a good balance of performance output, stability and fan speed. The clock speeds you see above are what will be used for the benchmarks.
A Quick Note about "Power Throttling"
A few days before this article went live, the maniacal “wizards” over at TechPowerUp posted a handy little command line prompt for GPU-Z which supposedly eliminates the power throttling on GTX 580 cards. Basically, this feature is supposed to limit the amount of amperage which is sent to the GPU when certain “power viruses” such as OCCT and FurMark are detected.
Some believe that eliminating this built-in protection will also open up overclocking on GF110-based GPUs but fortunately, that wasn’t meant to be for any of our samples…with air cooling at least. Even when enabling the command line override in GPU-Z, we weren’t able to get one extra Mhz out of any GTX 580.
However, our results can’t be taken as a benchmark if you are using more exotic forms of cooling. There may very well be a point where highly overclocked frequencies smash head first into the limitations NVIDIA placed upon the GTX 580. We just weren’t able to reach them with the reference heatsink. Then again, from our understanding NVIDIA has simply implemented a software solution to cut off Furmark et all at the knees rather than true hardware monitoring of input current.
Just remember that while ASUS maintains their warranty as long as you overclock and increase the voltage from within Smart Doctor, eliminating the GTX 580’s power throttling will basically void your warranty from any of the board partners we have talked to. Honestly though, for anyone not interested in possibly overclocking far above and beyond the limits of what air cooling will allow, disabling this power throttling technology would be completely pointless.
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