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Graphics Overclocking: Getting The Most From Your GPU

Overclocking: Nvidia And D.O.T.

MSI D.O.T. 182.06

Once more, we’d like to offer a word of warning. Overclocking may damage your card, and if you make any changes, you do so at your own risk. Doing so may also void your warranty.

MSI’s Nvidia-based cards use the same D.O.T. (Dynamic Overclocking Technology) feature as the ATI models. Again, you can’t download it separately and are forced to use MSI’s modified driver instead if you want to take advantage of it.

While it’s a good deal fresher than MSI’s Catalyst-based driver, GeForce 182.06 is not as current as we would like. Nvidia’s official release is 186.16 at the time of writing (Ed.: a recent update to 190.38 increments Nvidia's GeForce suite yet again). The additional D.O.T. section is launched as a separate application in Windows. Just like its ATI counterpart, it comes with six predefined performance profiles. However, as it turns out, we could get far fewer of them to run stably.

Don’t let that fool you, though. Remember that MSI’s Lightning version of the GTX 260 (216 SPs) is factory-overclocked to begin with. While Nvidia’s stock setting for this card would call for a clock speed combination of 578/1,242 MHz (GPU/shader), MSI’s default setting already runs the card at 655/1,404 MHz. That the GPU and the shaders run at different speeds is typical of Nvidia’s designs.

O/C ModeClock Speed (GPU/Shaders/Memory)
Standard (default)655/1404/999
MSI D.O.T. Private668/1432/1018
MSI D.O.T. Sergeant681/1460/1038
MSI D.O.T. Captain694/1488/1058
MSI D.O.T. Colonel707/1516/107
MSI D.O.T General713/1530/1088
MSI D.O.T. Commander720/1544/1098

Again, you’ll most likely have to find out for yourself whether a setting will work with your card. Our sample was stable up to the “Captain” D.O.T. level, but wouldn’t go any higher. Installing Nvidia’s latest reference driver deactivates the D.O.T. feature, causing its control panel to vanish as well.

As long as the setting you have chosen works, you won’t actually notice a difference (aside from the performance, obviously). If your card features an optimized fan speed profile, the fan will spin up to deal with the extra heat generated by the higher clock speeds. We recommend a little tool called GPU-Z if you want to keep an eye on your GPU’s temperature. It can also monitor fan speeds, clock speeds, and some of your graphics card’s various other vital signs. Additionally, GPU-Z can also create a log file, which is very handy if you want to check back on your card’s performance later. 

Since you’ll only know you’ve found the ideal setting after the fact (namely, when you go over the log files or push your board one level too far), it’s best to keep your initial tests short. Normally, a GPU will reach its maximum temperature under load after two to five minutes. You should also take some readings at stock settings, allowing you to check on what’s changed, and to what extent. If the fan does not spin up, you need to keep a very close eye on the temperature.

To reduce the risk of damaging your card, you should start off with the smallest overclocking increment and apply the change. Since our Nvidia card is already overclocked by default, we have to be a little more cautious, since we’ll definitely reach its limits much faster. Once you’ve selected the profile you want to try, run a 3D benchmark to stress the GPU with the new settings.

You’ll know when you’ve exceeded your card’s limit if you see any of the following symptoms: rendering errors, inverted colors, a flickering screen, pixelation, solid blocks of color, or a frozen system. At that point, your graphics driver may restart, dumping you back to the desktop. Alternatively, your system may crash completely and restart, in which case you can forget about the increased clock speed.

  • dingumf
    What the hell, I thought this was a guide to overclocking the GPU as the title reads "Graphics Overclocking: Getting The Most From Your GPU"

    Then at the end Tom's Hardware screws me over and writes "Conclusion: It’s A Tie"

    Isn't this a tutorial?
  • they tell you how to overclock using CCC or riva tuner, or evga precision, they also tell you, overclocking = more performance at the cost of more power. what else do you want?
  • dingumf
    joeman42What is really needed is a "continuous" OC utility that can detect artifacts during actual use and adjust accordingly. I've noticed that my max OC tends to change each time I test and depending on the tool I test with (e.g., atitool, gputool, rivatuner, and my favorite, atitraytool). Some games, l4d in particular, crash at the slightest error. Others such as COD and Deadspace are somewhat tolerant. Games like Far Cry 2 and Fear 2 don't seem to care at all. It would be nice if the utility could take this into account.As for the tools themselves, Atitraytool has far and away the best fan speed adjuster, the dual ladder Temp/Speed is a model of simplicity. Plus, it can automatically sense a game and auto OC just for the duration. Nothing like this exists on the NV side (you must explicitly specify each exe). Unfortunately, I am on a NVidia card now and Rivatuner is pretty much the only game in town for serious tweaking. IT IS A DESIGN DISASTER! random design with no discernable structure. A help file which consist solely of the author bragging about his creation, without explanation as to where each feature is implemented or how to use it. And no, scattered tooltips is not an acceptable alternative. It took forever to figure out that I needed to create a fan profile and then a macro and then create a rules to fire the macro which contains the fan profile just to set one(!) fan speed/temp point (and repeat as needed). Sorry for the rant, but I really hate Rivatuner!
    Oh hello. That's what OCCT is for.
  • nitrium
    Rivatuner works just fine with the latest drivers (incl. 190.38). Just check the Power User tab and under System set Force Driver Version to 19038 (or in the articles case 18618) - no decimal point. Be sure that the hexidecimal display at the bottom is unchecked. All Rivatuner's usual features can now be accessed.
  • masterjaw
    I don't think this is intended to be an in-depth tutorial like dingumf perceives. It's just for people to realize that they could still get more from their GPUs using tools.

    On the other hand, I don't like the sound of "It's a tie". It looks like it is said just to show neutrality. ATI or Nvidia? It doesn't matter, as long as your satisfied with it.
  • quantumrand
    I must say, the HD 2900 is a great card. I picked up the 2900 Pro for $250 back in 2007 and flashed the bios to a modified XT bios with slightly higher clocks (850/1000). The memory is only GDDR3, but with the 512bit interface, it really does rival the bandwidth of the 4870. I can get it to run Crysis at Very High, 1440x900 with moderately playable framerates (about 25fps, but the motion blur makes it seem quite smooth). Really quite amazing for any 2007 card, let alone one for $250.
  • quantumrand
    Just a bit of extra info on the 2900 Pro...

    The Pros were bassically binned XTs once ATI realized that the card was too difficult to manufacture cheaply (something about the high layer count it takes to make a 512bit PCB), so in order to sell their excess cores, the clocked them lower and branded them as Pros. Additionally, they changed the heatsink specs as well, adding an extra heatpipe. Because of this, the Pros could often OC higher than the XTs, making them essentially the best deal on the market (assuming you got a decent core).
  • Ramar
    Overclocking a GPU generally isn't worth it IMO, but sometimes can give that extra push into +60fps average. Or to make yourself feel better about a purchase like myself; one week after I bought a 9800GTX they came out with the GTX+. A little tweaking in EVGA Precision brought an impressive 10% overclock up to GTX+ levels and left me satisfied.
  • manitoublack
    I run 2 Palit GTX295's and have had great success with palit's "Vtune" over clocking software. I believe it works with cards from other vendors as well. Easy to use and driver independent.

    Cheers for the great article
    Conclusion: It’s A Tie

    I didn't know they were in competition until I read that.....I too thought this was about overclocking a GPU in general, not which card you should buy. Once again Toms throws that little barb at the end to stoke the fires.

    I think they do this constantly to get more website hits.. If the can get a good ol' fanboy war on every article, they will get people coming back over and over again to add fuel to the fire. After all, the more hits they get, the more they get paid from their sponsors. Which BTW, seam to be taking up more real estate then actual content on this site these days.