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Making Lemonade: Overclocking Your Locked AMD Processor

Making Lemonade: Overclocking Your Locked AMD Processor
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Readers of this site are probably well aware of the overclocking potential in AMD’s Phenom II processors. Through CPU reviews, performance comparisons, picture stories, and “How To” guides, Tom’s Hardware has highlighted the hidden potential within these processors and detailed how to attain similar results at home.

From our explorations of the AM2+ or AM3 platform, using basic or extreme cooling, the one constant has been the use of a Black Edition Phenom II—and for good reason. These “unlocked” processors are specifically targeted at enthusiasts who want to squeeze more performance out of the product than they paid for.

This time, however, we’ll specifically look into overclocking a “locked” processor. We chose the AMD Phenom II X3 710, a roughly $100, 2.6 GHz triple-core chip. Though it certainly doesn't lack stock performance or core speed potential, a locked processor such as this one offers far less overclocking flexibility.

What exactly is a locked processor? Specifically, we’re referring to the “locking” of the CPU multiplier and, in the case of this AMD processor, the CPU VID (voltage ID). Actually, both values can be reduced, but they’re locked from being raised above their stock base value.

Taking a look at the equation core speed = CPU multiplier x reference clock, you can see that eliminating the ability to raise the CPU multiplier means any increase in core speed will need to come from raising the reference clock. This will, in turn, raise the HT (HyperTransport) link speed, northbridge speed, and memory frequency, which are also based on the reference clock. If you need a refresher on terminology or calculations, take a look back at this How To: guide.

To cool our retail Phenom II processor, we set the boxed cooler aside and used the Xigmatek HDT-S1283. However, to have any hope of pushing this processor up into the same range as a Black Edition, we also needed a motherboard capable of running a high reference clock. As seen in this motherboard roundup, the MSI 790FX-GD70 stands out as a winner in this area and should allow us to push this CPU to its air-cooled limit.

In this story, we’ll highlight a few different methods of overclocking our locked processor, including conventional BIOS overclocking, AMD’s OverDrive utility, and the 790FX-GD70’s nifty OC Dial. We’ll walk through these three methods, comparing both the experience and results achieved. Finally, we’ll take a brief look at the performance gained by overclocking the CPU, northbridge (NB), and memory.

Display 43 Comments.
Top Comments
  • 13 Hide
    sohei , August 27, 2009 8:56 AM
    it's about how to squeeze all performance from an locked cpu .
    this is a pro' article (head shot)
Other Comments
  • 13 Hide
    sohei , August 27, 2009 8:56 AM
    it's about how to squeeze all performance from an locked cpu .
    this is a pro' article (head shot)
  • 0 Hide
    nzprogamer , August 27, 2009 9:52 AM
    im a big amd fans, good stuff here, look forward to go back to amd
  • 5 Hide
    amdfangirl , August 27, 2009 10:50 AM
    Good article! Too bad I killed my AMD CPU :p 
  • 2 Hide
    brisingamen , August 27, 2009 12:48 PM
    great article, should be more like it,
    and a few more gaming benches wouldnt hurt either guys!
    speaking of headshots yes unreal tournament is probably the most important game to exemplify the value of overclocking and added framerates due to "headshots" and shtuff.

    keep up the good work!
  • 9 Hide
    Onus , August 27, 2009 12:50 PM
    stray_gatorWhat's the point of using a high-end mobo to overclock a mainstream/value cpu?

    Fair question; no one would likely do this IRL, but I think the point here was to see how high the locked CPU could go, so they used a premium mobo.
    Paul, now that we know what this specific CPU can do, would it be useful to now put it on a more typical mainstream mobo and see what one might get from the same chip under more typical conditions?
    The point would be to answer the following: if my budget just grew by $25, does it make more sense to buy a BE CPU or to get a more premium mobo?
  • 8 Hide
    haplo602 , August 27, 2009 1:37 PM
    stray_gatorWhat's the point of using a high-end mobo to overclock a mainstream/value cpu?


    because value mobos vary in stability much more than premium mobos. this article was just about the CPU limit, not the mobo limit.
  • 0 Hide
    Anonymous , August 27, 2009 1:43 PM
    Tom's should do a shoot-out between an i7 920 and a 965BE that's had the multiplier taken down to 13x(2.6ghz), then both OCed to the max on the northbridge alone. I'm sure that would close the gap atleast somewhat, but I'm interested to see exactly how much. Maybe they could screw around with the HyperTransport multiplier as well, it might turn out that AMD has been shooting itself in the foot with the unlocked multiplier, when more performance would be had if they were forcing people to use the northbridge.
  • 3 Hide
    Shadow703793 , August 27, 2009 2:38 PM
    Good write up; but PLEASE do NOT recommend OCing via Windows. Most pro's here will tell you that same thing. BIOS > Windows for OCing.
  • 1 Hide
    Shadow703793 , August 27, 2009 2:39 PM
    Also how about putting this under WCing or DIce/LN2? :D 
  • 1 Hide
    Ryun , August 27, 2009 2:49 PM
    In the performance gains and the cpu tweaking page the graphs for world in conflict are switched.
  • 7 Hide
    dirtmountain , August 27, 2009 3:28 PM
    Excellent article! Thank you for the work.
  • 0 Hide
    DarkMantle , August 27, 2009 3:45 PM
    Very good article!. Ryun is right, those 2 graphs for World in Conflict are switched.
  • 0 Hide
    Upendra09 , August 27, 2009 4:06 PM
    I was planning on OCing but this article has made me afraid to OC, it seems there are a lot more factors involved in this than i thought.
  • 0 Hide
    saint19 , August 27, 2009 4:43 PM
    Really good article, in the pass I has a X2 6400+, and only can overclok 100MHz....now with the 955 I have 600MHz more that the stock frecuency....
  • 1 Hide
    cybot_x1024 , August 27, 2009 5:40 PM
    nice article.
    Amd has really improved overclockability with the dragons.
  • 2 Hide
    bustapr , August 27, 2009 6:36 PM
    wow great increases fom a triple core. 2.6 to 3.7 is great!
  • 7 Hide
    Anonymous , August 27, 2009 6:39 PM
    Shreder: You are a perfect example of a brainwashed sheep. Core i7 has been shown to have a definite advantage in:

    Video Rendering(I don't care, maybe you do)
    Synthetic Benchmarks(yawn)
    Specific games that have been "optimized"(rigged) to perform better on an i7

    Other than that, the advantage ranges from neglible to non-existant. Unfortunately, there are people like you who swallow every bit of the fanboy articles with cherry-picked benchmarks...
  • -1 Hide
    Boxa786 , August 27, 2009 7:29 PM
    Like Shadow said, its obviously a really good cpu, for overcloking from amd,

    lets see how high it can go ;D
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