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Overclocking Results

Six New Phenom II And Athlon II CPUs From AMD
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We wanted to see if these new AMD models have more overclocking headroom than their predecessors, so we performed some quick and dirty overclocking tests.

In the case of the Phenom II X2 560 and Phenom II X4 970 Black Edition CPUs, we simply raised the voltage to 1.475 V, along with the CPU multiplier, until we figured out the limit of Prime95 stability. The Phenom II X6 1075T is a little trickier since it is not a Black Edition processor and its CPU multiplier is locked. In this case, we increased the voltage to 1.475 V and the reference clock speed until we achieved the highest stable setting (each processor's overclocking details are reported below).

The Phenom II X2 560 makes it to 4 GHz, which is just about exactly what we got out of our Phenom II X2 555 at the beginning of the year. However, our attempt to unlock dormant CPU cores (in order to turn the X2 into an X3 or X4) was met with failure. We were actually a little surprised, because this is the first Black Edition Phenom II X2 that we haven’t been able to successfully unlock. The 700 MHz overclock helps performance, regardless.

Our experience with the Phenom II X4 970 is slightly different. Our first sample was able to hit 3.9 GHz through multiplier-based overclocking, which is about what we expect to achieve with a Phenom II X4 965. However, we also have a Phenom II X4 970 on hand that benefits from an AMD process improvement.

The newer revision can be identified with the letters “AACDC” on the lid, as opposed to the previous sample that read “AACAC.” AMD's representative assures us that the newer revision is the only one that will make it to retail channels. Both CPUs are revision RB-C3 and Stepping 3, according to CPU-Z, but the new version does achieve a higher overclock of 4.1 GHz. Prime95 stress tests run fine, but SiSoft Sandra arithmetic benchmarks crash and we had to raise the voltage to 1.55 V in the BIOS to achieve stability. This is a little higher than the 1.5 V maximum we usually use, but the temperatures remained quite low, so we allowed ourselves to indulge a bit.

The multiplier-locked Phenom II X6 1075T managed to make it to 3.75 GHz at 1.475 V with a bus increase to 250 MHz. This overclock really revitalizes this CPU, as you can see in the benchmarks.

We also include the overclocked Core i5-750 results from our last System Builder Marathon:

In the SiSoft arithmetic CPU benchmark, the overclocked Phenom II X4 and X6 show large improvements over the stock speed, but the dual-core Phenom II doesn’t demonstrate much of an advantage when pushed. The Core i5-750 shows a huge boost in the Dhrystone results, but the Whetstone numbers fall short of the overclocked Phenom II X4 970 and the stock Phenom II X6 1075T.

We choose TMPGEnc for our application benchmark because it has two different encoding algorithms that take advantage of varying processor strengths. While the DivX codec demonstrates a huge performance increase with the Phenom II X6’s hexa-core architecture, the Xvid codec prefers raw speed and Intel’s design.

With StarCraft 2 as our game benchmark, you can see the overclocked Phenom II X6 1075T surpasses even the 4.1 GHz Phenom II X4 970 by a small margin. The overclocked Core i5-750 really shines here, though, sailing by all of the other processors.

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Top Comments
  • 18 Hide
    eklipz330 , September 21, 2010 4:27 AM
    aznshinobiDo I hear comeback from AMD? Hopefully the Bulldozer shows results with the AM3+/AM3r2 in benchs.

    this is hardly a comeback, they simply filled in segments on the price range with not-so-new products. a little bump in speed, probably better binned, and a few more bucks. seems like the logical thing to do at this point, until bulldozer anyhow
  • 10 Hide
    cleeve , September 21, 2010 5:26 AM
    MoreCores...1075T can not, and it's more expensive than i7 920.


    At $145, he 1075T is $40 cheaper than any Core i7 I can find online.
Other Comments
  • 1 Hide
    aznshinobi , September 21, 2010 4:20 AM
    Do I hear comeback from AMD? Hopefully the Bulldozer shows results with the AM3+/AM3r2 in benchs.
  • 7 Hide
    gkay09 , September 21, 2010 4:23 AM
    Good article and the 1075T is a good addition to the 6-Core line...
    And most of all, thanks for confirming that all the current socket will be replaced next year including AMD.
  • 1 Hide
    scifi9000 , September 21, 2010 4:25 AM
    I'd love to see these new chips pitted against the T1000 processor.
  • 18 Hide
    eklipz330 , September 21, 2010 4:27 AM
    aznshinobiDo I hear comeback from AMD? Hopefully the Bulldozer shows results with the AM3+/AM3r2 in benchs.

    this is hardly a comeback, they simply filled in segments on the price range with not-so-new products. a little bump in speed, probably better binned, and a few more bucks. seems like the logical thing to do at this point, until bulldozer anyhow
  • -6 Hide
    duk3 , September 21, 2010 4:28 AM
    I'd rather it was a 970T at 3.6 ghz with turbo up to 4.1ghz.
    Then again, who wouldn't?
  • 4 Hide
    Gin Fushicho , September 21, 2010 5:06 AM
    I'm still waiting for Bulldozer, I hope that Bulldozer makes AMD king again. If so I'll buy another AMD system. I've been waiting since the early Dualcore Windsor cores.
  • 4 Hide
    spentshells , September 21, 2010 5:12 AM
    nothing new here good on AMD if they keep the prices the same
    the 645 and 450 are really crazy good deals
  • 10 Hide
    cleeve , September 21, 2010 5:26 AM
    MoreCores...1075T can not, and it's more expensive than i7 920.


    At $145, he 1075T is $40 cheaper than any Core i7 I can find online.
  • 3 Hide
    TheStealthyOne , September 21, 2010 5:30 AM
    Yay! :) 
  • -1 Hide
    idoln95 , September 21, 2010 5:34 AM
    are these temps with stock cooler? they seem to be a big off...


    oh sorry, missed the minus ambient part...

    wow, thats kinda hot.... (30C ambient in here :(  )
  • 0 Hide
    RazberyBandit , September 21, 2010 5:34 AM
    CleeveAt $145, he 1075T is $40 cheaper than any Core i7 I can find online.

    I think you meant $245, Don.

    I find it great to see the Phenom II 970 still capable of Cool'n'Quiet idle mode while overclocked. C'n'Q doesn't work on my 720BE at any speed over 3.2GHz. Is that something common to the C3-Stepping models?
  • 9 Hide
    AMW1011 , September 21, 2010 5:38 AM
    Holy shit, 3.5 Ghz stock. I know it really doesn't mean much, but I still like the sound of that.
  • 9 Hide
    scrumworks , September 21, 2010 6:07 AM
    Sandra is very bad synthetic benchmark. It clearly favors Intel architecture and the differences are not that dramatic in real world applications. With enough bribes you seemingly can get nice optimizations.
  • 3 Hide
    dirtmountain , September 21, 2010 7:04 AM
    A very well written article. It covered all the bases and was very informative. Damn good work, it's why people check in at Tom's Hardware.
  • 2 Hide
    jgv115 , September 21, 2010 7:30 AM
    I'm happy that my Core i5 750 stands up to 2 updates (speed bumps) of the Phenom II 955 (the 965 and 970). It even beats the 1075T!

    I think the 750 is still the better CPU in it's price range.
  • 0 Hide
    liquidsnake718 , September 21, 2010 7:41 AM
    Yeah there should hve been at least a core i3 fo good measure against the AMD 2's...
  • 3 Hide
    ThePeacemaker10 , September 21, 2010 8:33 AM
    How are the StarCraft 2 benchmarks possible? I NEVER drop below 55 fps and I'm using an Athlon II X3 445 with an HD 5750 and 4 GB of RAM. I don't get it.
  • 1 Hide
    ThePeacemaker10 , September 21, 2010 8:42 AM
    ThePeacemaker10How are the StarCraft 2 benchmarks possible? I NEVER drop below 55 fps and I'm using an Athlon II X3 445 with an HD 5750 and 4 GB of RAM. I don't get it.


    I should also mention I'm running on High with 1680x1050 resolution.
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