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Test Platform And The Competition

Efficiency: Optimizing The Clock Rate Of AMD's Phenom II X6
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Test Motherboard: Asus Crosshair IV Formula

The Crosshair IV Formula is Asus’ 890FX flagship for the Socket AM3 platform. It is extremely well-equipped and very suitable for overclocking, thanks to a powerful 8+2 phase voltage regulator design. CrossFireX can operate either through two x16 PCI Express links running 16 lanes each, or one x16 PCIe slot sporting 16 lanes and two more x16 connectors running at eight lanes each. Asus adds a JMicron JMB363 controller that offers UltraATA and an NEC controller that enables two USB 3.0 ports. SATA 6Gb/s is supported by the SB850 southbridge—an area where Intel’s core logic is falling behind.

Asus offers its TurboV Evo and OC Profile tools to facilitate overclocking, but we used AMD’s OverDrive utility instead, since it’s not proprietary and can be used on most AMD motherboards.

Auto-Voltage Issues

Some motherboards, such as the Crosshair IV Formula, automatically adjust the processor voltage if you increase the chip's multiplier. In this simple example, we went from 3.2 GHz and a 16x multiplier to 3.4 GHz and a 17x multiplier. The result was a 0.12V effective increase in Vcore, which isn’t bad since it can improve CPU stability at overclocked settings. However, the overclock was small enough to not impact stability (rendering that voltage bump unnecessary), which we found out by manually setting the voltage back to 1.25V. Moreover, the voltage increase had a severe impact on system idle power, sending it rocketing up by 40 watts.

The Asus motherboard we used would automatically increase processor voltage when the CPU multiplier increases.

We switched the processor voltage back to regular values manually to make sure that idle power stayed in a reasonable area.

Competitors in this Roundup

We decided to include a few additional processors to be able to evaluate the overclocking results of the Phenom II X6. The contenders were a Phenom II X4 965 at 3.4 GHz and four Intel CPUs: the six-core Core i7-980X flagship, the quad-core Core i7-975, the Core i7-870 on an LGA 1156 interface, and the mainstream Core i5-750. Adding a dual-core Core i5 processor would probably have been appropriate from a pricing standpoint, but we doubt that the comparison would be very relevant. More cores mean lots of additional performance for as long as you’re executing threaded applications. For conventional software, you can save money and stay with a fast dual-core CPU.

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Top Comments
  • 20 Hide
    The Greater Good , June 14, 2010 8:00 AM
    FTFA:
    Quote:
    Adding a dual-core Core i5 processor would probably have been appropriate from a pricing standpoint, but we doubt that the comparison would be very relevant.


    I disagree. If I had 200 dollars to spend on a CPU, why do I need to know how a 1000 dollar CPU stacks up to a 200 dollar CPU? It's clearly out of my price rage. Showing a side-by-side comparison of what Intel offers and what AMD offer at the same price-point would be very relevant.
  • 17 Hide
    welshmousepk , June 14, 2010 8:49 AM
    really wish they had included the 1055t in this article.

    is it worth spending the extra 100 dollars when overclocking is taken into account?
  • 13 Hide
    wintermint , June 14, 2010 6:13 AM
    I hope Intel Fan go away because I don't want to hear about $1000 CPU when you can have these for 1/5 the price... affordable and efficient
Other Comments
  • 13 Hide
    wintermint , June 14, 2010 6:13 AM
    I hope Intel Fan go away because I don't want to hear about $1000 CPU when you can have these for 1/5 the price... affordable and efficient
  • 11 Hide
    darkpower45 , June 14, 2010 6:20 AM
    if only intel would bring out a 32nm quad core already...
  • 8 Hide
    HansVonOhain , June 14, 2010 6:20 AM
    Great article. Need to do these article on more processors that are affordable to the masses.
  • 12 Hide
    duk3 , June 14, 2010 6:21 AM
    Interesting article.
    I am interested in seeing Bulldozer released.
  • -2 Hide
    Stardude82 , June 14, 2010 6:40 AM
    Wow...AMD's silicon is pretty awesome and a hexa-core is a great thing to compete on the desktop, but when you look at the new i7 875K ($320), all arguments about platform aside, I don't think AMD's value lead here is all that clear. This doesn't even include your previous analysis the10-20% efficiency increase which overclocking the Lynnfields can yield.
  • 10 Hide
    lonepasserby , June 14, 2010 7:38 AM
    How long will AMD make us wait for Bulldozer? Serious fans would probably be suffocating right now by holding their breath for its release.
  • 2 Hide
    DjEaZy , June 14, 2010 7:50 AM
    ... i bookmark this one... when i get my 1090T, this article will be usefull...
  • 20 Hide
    The Greater Good , June 14, 2010 8:00 AM
    FTFA:
    Quote:
    Adding a dual-core Core i5 processor would probably have been appropriate from a pricing standpoint, but we doubt that the comparison would be very relevant.


    I disagree. If I had 200 dollars to spend on a CPU, why do I need to know how a 1000 dollar CPU stacks up to a 200 dollar CPU? It's clearly out of my price rage. Showing a side-by-side comparison of what Intel offers and what AMD offer at the same price-point would be very relevant.
  • 0 Hide
    lothdk , June 14, 2010 8:39 AM
    What I would have found more interesting is a comparison between an overclocked 1090T and an overclocked i7 930 which costs approximately the same (unless you have access to microcenter and can get the i7 for $200).
  • 11 Hide
    joytech22 , June 14, 2010 8:40 AM
    dragonfang18ok... AMD 3.4Ghz for $300... Intel I7 920 $280 at 3.6Ghz.


    You forgot to mention the i7 isn't stock..
  • 17 Hide
    welshmousepk , June 14, 2010 8:49 AM
    really wish they had included the 1055t in this article.

    is it worth spending the extra 100 dollars when overclocking is taken into account?
  • 10 Hide
    zaodrze244 , June 14, 2010 9:06 AM
    why not theres no tests results in games like GTA IV or Flight Simulator X, where the cores are heavily used. without this article is useless
  • 0 Hide
    _SirO_ , June 14, 2010 9:07 AM
    Could have added a performance / power chart with frequency increase
  • 0 Hide
    Lmeow , June 14, 2010 9:16 AM
    welshmousepkreally wish they had included the 1055t in this article. is it worth spending the extra 100 dollars when overclocking is taken into account?


    Probably not, but then some would argue the 1090T Black Edition might be higher binned and would be easier to overclock because of the unlocked multiplier.
  • 5 Hide
    Arock , June 14, 2010 11:15 AM
    Should include the 1055T...Can it same efficiency at 3.4Ghz like 1090T..?Then we can judge its efficiency & performance also..Y spend xtra 100$ if that performance we in 200$???
  • 0 Hide
    Reynod , June 14, 2010 12:12 PM
    What a great article.

    I am stunned.
  • 4 Hide
    lukeeu , June 14, 2010 12:20 PM
    So running a CPU at 400W isn't stable huh?
    I'd like to add that if you upgrade your AMD rig you don't have to spend extra 120$ on mobo and 150$ on new ram and Intel already announced that next cpu after i7 will have a new socket. I've found benchmarks that show phenom x2 gets only 2% performance hit while running on ddr2. Does anyone know the figures for X6?
  • 3 Hide
    Onus , June 14, 2010 12:29 PM
    This article tells me that the 1090T performs very well if you overclock it even a little; and that it has to be overclocked to do well. Great; if I buy one there's no way now that I won't overclock it. Now, please take an equivalently-priced Intel CPU+motherboard+RAM combo and overclock it to the same [non-extreme] degree. Then compare the performance and the value. Any possible fanboy differences aside, that will tell me which CPU to buy. Thank you.
  • 3 Hide
    COLGeek , June 14, 2010 1:33 PM
    I have had a 1090T BE for several weeks now and while I am not an overclocker, generally, I have been tinkering with this CPU. This article confirms the performance I have been seeing as I tweak the processor. Video rendering (as I convert 20+ years of VHS and Digital 8MM to DVD) has been phenomonal (no pun intended) and getting better as I refine my settings.

    While I am a long time AMD Fanboy (going back to my first AMD, a 386-DX 40, in 1992), one must be impressed with how much processor you can get for the money.

    Get one for your self, you won't be sorry. HOOAH!!!
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