Quick take: 6850 and GTX 460 overclocking

We simply did not have time, in preparing our review of the new Radeon HD 6800 series GPUs and Nvidia’s hyper-clocked GTX 460 response, to make any serious attempts at overclocking those cards. Happily, I’ve been able to take a little bit of time since then to see what I could squeeze out of a couple of the cards in question. What we found is tremendous headroom in of both of the major mid-range GPUs, especially when combined with custom coolers.

Our first victim was XFX’s version of the Radeon HD 6850. This card is a little shorter than AMD’s reference design, and it has a custom cooler that we’ve found to be tuned with a bias toward keeping temperatures low rather than noise levels. Generally, we’d prefer a less aggressive fan speed profile, but for this particular mission, the extra cooling was just what the doctor ordered. We chose to focus on the 6850 rather than the 6870 simply because the lower-end models based on a particular GPU tend to have more overclocking headroom.

After futzing with the Overdrive auto-tune tool in AMD’s control panel, we quickly realized that software wasn’t gonna cut the mustard. The core GPU clock slider in that utility stops at 850MHz with the 6850, and our card was perfectly stable at 850MHz at its stock voltages.

At the suggestion of Tarinder from Hexus, we decided to try Sapphire’s TRIXX overclocking utility, instead, which offers both higher clock speeds and voltage control. Using TRIXX to tweak and MSI’s Kombustor tool (a FurMark type GPU burn-in app) to confirm stability, we learned that the 6850 would do 900MHz quite happily at its stock voltage. Bumping up the GPU voltage allowed us to range even higher.  The GPU would operate at 960MHz, but we saw visual corruption in Kombustor all the way up to the utility’s peak of 1.3V. Ultimately, we settled on a max stable (and visually correct) GPU clock speed of 950MHz.  We tested memory separately and determined that 1200MHz was its peak speed, and that memory speed worked well in conjunction with our 950MHz GPU clock.

At those frequencies, the card operated at a somewhat reasonable 84°C, with the fan at 90% of peak. We noticed that pushing up to 1.3V and higher GPU clocks caused temps to rise to near 90°C. I expect this card’s overclocking headroom is somewhat limited by its cooling. 

Still, 950/1200MHz is a huge step up from the 775/1000MHz default clocks on the 6850, enough to put the overclocked 6850 ahead of a stock Radeon HD 6870 in terms of theoretical ROP rate and memory bandwidth.  (The 6870 still has more peak texture and shader throughput, though, thanks to its two additional active SIMDs. We’ve not yet explored the overclocking headroom on the Radeon HD 6870, but we’ll try to squeeze it in when we can.)

Speaking of the 6870, our next victim, the MSI Hawk Talon Attack, is more of a competitor for it than for the lower-priced 6850. We chose to overclock this MSI card for a couple of reasons. First, because it’s obviously built for overclocking, with a trick cooler and higher-grade GDDR5 DRAM rate for 0.4-ns operation. Like the XFX, this card’s cooler runs loud but keeps GPU temperatures very low. Second, the GTX 460 is mostly a known quantity, but we wanted to see just how much headroom was left in one of these new, higher-speed versions of it. Heck, the stock GPU frequency on this thing is 810MHz, well above the GTX 460 1GB’s original 675MHz base. Does the GF104 have anything left to give?

Turns out the answer is a resounding “yes.” MSI’s Afterburner utility was my weapon of choice here, because it allowed me to raise clock speeds and adjust three separate voltage values: the GPU, memory, and the PLL. After lots of iterations and testing, we worked out a best stable config of a 940MHz GPU core and 1175MHz memory (which shows as 2350MHz in Afterburner), with all of the voltage values turned up as much as possible, +100 mV for the core and memory and +30 mV for the PLL. We’re showing 950MHz in the image above, but that speed wasn’t 100% stable in our game test.

Interestingly, we didn’t see any visual corruption in Kombustor with the GF104; it just crashed when it was unhappy. Also—and this may be related—this card’s cooler proved to be much more effective at keeping temperatures in check. The picture above, from the end of a long load test, shows a 72°C reading for the GF104.

Both cards are pretty darned loud when overclocked like this, but those speeds were sustainable, at least in our limited experience with Kombustor’s crazy-intensive load test.

You can see how the overclocked 6850 pretty much matches a 6870, performance-wise. That is a lot of power for 180 bucks.  Meanwhile, the higher-priced (~$215) GTX 460 Hawk Talon Attack sinks its claws into a relative, the GTX 470, committing raptor fratricide. Both of our overclocked cards gain about 5 FPS on average here, or over 10% in each case.

Extensive overclocking has its downsides, too. That additional voltage translates into more power consumption at the wall socket. You’re not really treading into difficult territory with the 6850, but our GTX 460’s power draw is pretty considerable—something you may want to keep in mind if you’re planning on trying a similar feat at home.

Comments closed
    • chriso11
    • 9 years ago

    I generally avoid overclocking hardware. In Nvidia’s case, I would be doubly hesitant, given Nvidia’s history of problems (e.g. google for nvidia gpu failures ).

    Those who forget the past are doomed to repeat it…

    • sweatshopking
    • 9 years ago

    ARRRGGHGHGHGH RAGE ABOUT SOME COMPANY!! DAMN THEM AND DAMN YOU!!!!

    • rechicero
    • 9 years ago

    #55 I don’t know if you replied the wrong post or simply didn’t understand a thing…

    • potatochobit
    • 9 years ago

    I would like to see a 6870 overclocked so I can make my decision this week

    • HurgyMcGurgyGurg
    • 9 years ago

    Anyone know where can you download TriXX? Google isn’t popping up much.

    Sapphire’s website shows “coming soon” for the download link. Is it bundled with only cards right now?

    Thanks.

      • billyconnection
      • 9 years ago

      You need to register your Sapphire card and become a member to download.

      I thought I would respond since I didn’t know either when I first read this article. Asus software will let me overvolt and overclock, but wont let me save profiles. Boo. Waiting for TRIXX…

      I <3 my 6850!

    • rechicero
    • 9 years ago

    #41 I’d say your problem is what Anand said about nVidia “asking” them to use overclocked cards. We all know that nVidia wanted exactly the articles you wrote, and that can’t be good.

    I’m sure you aren’t biased, but you’re misguided. Most people researching for a purchase only look the diagrams. That’s why the “halo effect” works. Should they read the articles? Sure. But they don’t. And if you didn’t want to write a direct comparison, maybe you shouldn’t have done that in the diagrams (remember, what most people actually read).

    Anyway, I’m sure you’ll see what was your mistake and won’t do that again.

    • Fighterpilot
    • 9 years ago

    For all the fawning over the GTX460 the fact remains that both the 6850 and 6870 are faster at stock than their counterparts the GTX460 768MB and 1 GB versions.
    Overclocking your video card is the domain of a very small enthusiast section of the market.
    Most of my computer savvy friends buy high end video cards yet none of us overclock them as it makes little difference in game image quality or feel yet adds to instability and heat/power draw for the system.
    The Radeons have a newer feature set that gives them a solid advantage over CUDA/WUDA/SHUDA as well.

      • travbrad
      • 9 years ago

      How are those their counterparts though? A 768MB GTX460 is $160 ($140 after rebate) vs $180+ for the 6850. Even the moderately OCed 1GB cards are $200 or less ($170-180 with rebate) compared to $240 for the 6870.

      You are certainly correct in saying the 6870 is faster than a stock 1GB GTX460, but they are also $50 more at present, and stock 1GB cards are hard to even find.

      Let’s not forget either that these “overclocked” GTX460s aren’t really overclocked in the traditional sense of the word either. You buy them and they come with those higher clocks straight out of the box, and they are guaranteed/warrantied to work at those speeds. The user doesn’t have to do anything special whatsoever. You can however get some more mhz out of them if you are into OCing.

      These higher clocked GTX460s are not “a very small enthusiast section of the market”, they basically outnumber the “stock” clocked cards.

        • Fighterpilot
        • 9 years ago

        The GTX*[<460<]* we are talking about is widely available pre overclocked. I was referring to the small amount of people that then overclock their new (pre overclocked)cards. Theoretical limits don't interest me much.How they arrive is how they should be judged as a rule. I hope that when TR does its test of the new GTX580 it will spend a whole page and a good part of the conclusion on the merits of a fully overclocked Cayman XT and Antilles 6990X2 so that a nice comparison can be drawn.

          • travbrad
          • 9 years ago

          Wow it was really late on a Sat night when I typed that, guess I was stuck 6 months in the past :p Fix’d

    • l33t-g4m3r
    • 9 years ago

    940 mhz is a very high OC, amazing really, but obviously not every card sold will be able to reach that.
    One interesting thing that this test shows is that in terms of overall efficiency, the 470 is actually a better card than the overclocked 460.

    The 6850 seems to be a pretty good overclocker, and does pretty good on power use.
    I’ve read a few reports on the 6870, and they don’t seem to overclock as well, making the 6850 the better OC card of the two.
    However, if I was going to buy a card tomorrow, it would be the 6870 because I don’t like leaving things to chance.
    I’d still like to see some more overclocking editions come out before making any final decisions.

      • Meadows
      • 9 years ago

      High? Wait till you see the 1000 MHz GTS 450.

        • l33t-g4m3r
        • 9 years ago

        Interesting, but I can’t think it would be worth bothering with, being a budget card. Power use, heat, and fan noise might be an issue, and would it even be worth it for the performance?
        The 460 and 6850 IMO are the only cards worth overclocking because they can actually reach the next performance level by doing so.

      • Goty
      • 9 years ago

      I’ve actually seen the opposite with the 6870. I’ve seen quite a few reports of samples that overclock to a bit over 1GHz with little issue.

    • geekl33tgamer
    • 9 years ago

    I have to say that I am mightly impressed by how good the GF104 chip is. With performance benches like that, why on earth would anyone get the GTX 480 at more than double the price of the 460?

    Looks like a GTX 460 really is the card of the moment, and may take some time to get a better card from either camp at this price point. Anyone wanna buy a couple of 5770’s off me? They are not very old… 🙂

      • sweatshopking
      • 9 years ago

      how much you want for them…?

      • Freon
      • 9 years ago

      If you have a pair of 5770s it will probably take more than a single moderately overlocked GTX 460 to beat it. You don’t see 5770 CF in many benchmarks anymore (and I probably wouldn’t suggest anyone go that route right now for the money), but it’s not a slow setup by any means if you already have it or find a couple of cheap 5770s on the used market.

        • kc77
        • 9 years ago

        I was thinking the same thing. CF’d 5770 aren’t slow by any means. Worse case is that they are a frame or two slower than a 5870 @1920 however it will beat it in many games though (and not by small margins either).

    • flip-mode
    • 9 years ago

    Wow, very nice of you to look at overclocking Scott. Excellent results too! Your efforts are very much appreciated. Scott, do you find AvP to be a decent overall benchmark or did you just pick the bench at random? Just curious if there’s a bellwether benchmark out there.

    The GTX 460 is so impressive, or, rather, Nvidia really castrated the heck out of that cards’ specs! Why, Nvidia? I understand not wanting to commit fratricide, but there’s a point at which it makes sense. Nvidia’s vendors have saved its GTX 460 bacon. Were it not for those vendors’ higher clocked cards the GTX 460 would not have looked competitive with the 68xx cards. I hope Nvidia appreciates that fact.

    The 6850 is very impressive too! Nice to see a highly overclockable Radeon – the 6850 is the most overclockable Radeon I’ve seen. With that in mind, here is little luster to the 6870 at its current price – 33% more than the 6850. The 6850 is a very tempting card. But the time doesn’t feel right yet – the recipe is missing one ingredient and that is some really excellent cooling solutions from the card vendors. I’m not impressed with XFX’s cooler and the reference cooler ain’t so hot either. MSI needs to slap the Hawk’s mammoth cooler on a 6850!

    Thanks again Scott!

      • Deanjo
      • 9 years ago

      l[

        • flip-mode
        • 9 years ago

        Hmm, I think you’re talking about something totally different. You’re talking about a “value add” or just plain old product differentiation; you’re talking about vendors making product tiers from the very same product.

      • FuturePastNow
      • 9 years ago

      l[

    • ThorAxe
    • 9 years ago

    #22, I have six 12cm case fans plus a 14cm and 12cm fan on the NH-D14 in my case (CM Staker) so air flow should not be a problem.

    However, I suspected that myself so I switched slots early in my testing just to check, but it made no difference to the clocks whatsoever.

      • Voldenuit
      • 9 years ago

      I guess the take home message is that overclocking is never guaranteed, so everyone at home thinking to hit 1000 MHz on their 460 should take note. 😛

    • basket687
    • 9 years ago

    Just a question: When you measure the load power consumption for a graphics card, how do you measure it? Do you run a game, 3dmark, furmark, or something else?

      • Firestarter
      • 9 years ago

      They use L4D2, because graphic cards tend to run hot in that game IIRC

        • Meadows
        • 9 years ago

        The Starcraft II menu should be enough.

          • Goty
          • 9 years ago

          Only for NVIDIA cards. 😀

    • Ditiris
    • 9 years ago

    Thanks for the quick compare Scott, I was hoping we’d see something like this. I’d certainly be interested in a more thorough overclocking comparison. I’m somewhat surprised the 6850 temperatures were so high, and that the 460 still had quite a bit of headroom left. Keep up the good work.

    • Bensam123
    • 9 years ago

    The overclocking utility you want for AMD cards is literally called “ATI Tray Tools”. Gives you every sort of twinking and overclocking option you’d want.

    • Voldenuit
    • 9 years ago

    Would appreciate sound level measurements at idle and load. Also, how much louder is the MSI cooler than the Gigabyte cooler (which is recycled on its GTX 460 and HD 6870 cards)?

    • kuraegomon
    • 9 years ago

    “Raptor fratricide” = epic. Damage, you just graduated to one-liner emperor in my book 🙂

    • SubSeven
    • 9 years ago

    l[

      • OneArmedScissor
      • 9 years ago

      My 6600GT idles at almost 70C and I’ve been running it eight or more hours a day for five years. So…at least five years.

      • Meadows
      • 9 years ago

      You can’t with that wattage. In fact, people tried to cook eggs on the GTX 480 and still failed. You need more output for that.

        • flip-mode
        • 9 years ago

        I imagine if you designed the proper cooking vessel you could still make it happen with the 6850’s wattage. The vessel would essentially need to be an insulated heatsink – pull the heat in from the chip but not let that heat dissipate. Think of a soup can with insulation wrapped around it. It’d still probably take a while to cook that egg, but I think it would get done.

          • Meadows
          • 9 years ago

          Yes, but then that wouldn’t be much of a graphics card, because the collected heat would result in temperatures that don’t allow for such chips to actually function.

            • flip-mode
            • 9 years ago

            Yes, of course. I forgot that we were talking about the practicalities of cooking an egg on a video card rather than just the theoretical possibility. You win yet another important victory, Meadows!

    • phez
    • 9 years ago

    940mhz 460? That’s the highest OC /[

      • geekl33tgamer
      • 9 years ago

      Agreed, and it doesn’t even get “silly” hot neither – Unlike the GTX 480 (Or previous gen GTX 2xx cards).

      • pot
      • 9 years ago

      I’ve seen some of the MSI hawks hit 1,000mhz on the xtremesystems forum.

        • phez
        • 9 years ago

        I took at look at those threads. Some oc’d 460s are running as fast as oc’d 6870s, atleast in 3dmark vantage. Pretty surprised, again.

          • kamikaziechameleon
          • 9 years ago

          The temps are still the show stopper, I stopped buying nvidia because the temps I got on my 8800 GTS 640 and 9800 GX 2 where ridiculous and contributed to crashes and lock ups without overclocking. I got the 4870 1 Gb and have been enjoying the phenominal system temps, I hope that a step up to the 460 1 Gb will keep things running smoothly.

    • KamikaseRider
    • 9 years ago

    Forget what i said before. I missed a comma.

    PS.: I have the impression that the 6870 would go easily over 1000MHZ. Anyone thought about that?

    • Damage
    • 9 years ago

    I just chose a couple of cards and overclocked them. It is not intended to be a direct comparison, just more information about each. The article notes the differences in price between them.

    • Derfer
    • 9 years ago

    I’m confused. Why did you put a full 460 against the 6850? The 768 version is in the same price bracket as the 6850. Seems like a random comparison.

    • Bauxite
    • 9 years ago

    l[

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