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Efficiency: Optimizing The Clock Rate Of AMD's Phenom II X6

Efficiency: Optimizing The Clock Rate Of AMD's Phenom II X6
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AMD’s six-core CPU is affordable (at least, compared to Intel's Core i7-980X). We're overclocking the Thuban design to see if its efficiency improves from faster clock rates. Comparisons to other quad- and hexa-core processors provide some perspective.

The new Thuban-based six-core Phenom II X6 processor is available in two different flavors: 2.8 GHz and 3.2 GHz. Both come with the new Turbo CORE feature that dynamically increases the clock rate of up to three cores. However, the Phenom II X6 doesn’t necessarily run at maximum efficiency when it's operated at stock speeds. In fact, a reasonable overclock provides a solid increase in performance per watt.

Today we determine the ideal clock speed and look at the maximum overclocking speeds using air cooling, because this is where you want justification for spending those extra dollars compared to quad-core processors.

AMD is Back

The new Phenom II X6 processor could be a turning point for AMD, helping the company back into the performance segment, despite the fact that it still trails Intel's Core i7 CPUs by a measurable margin. Intel still has a major advantage in overall performance thanks to higher performance per clock, and it also maintains the lead when it comes to power use due to its efficient Nehalem architecture. Some of the company's newest CPUs employ 32 nm  manufacturing, which serves to extend Intel's lead in efficiency. If you're looking for a definitive statement to describe the state of desktop processing, Intel is technically superior. Period.

However, Intel’s benefits don’t come cheaply. The flagship Core i7 CPUs cost roughly four times more than AMD’s six-core Phenom II. And you certainly don't get four times more performance, either. It's more like a quarter or a third more. Hence, these products are only attractive to professional users and the lucky ones with loose budgets.

The six-core Phenom II X6 is much more affordable, though it can’t pull away from solid quad-core offerings when it comes to gaming and single-threaded threaded applications.

Mainstream price points are probably more relevant for most of us. You could either say that Intel is gouging because it can or that AMD is more aggressive on pricing because it has to be, but our overall experience tells us that you get more value in the AMD portfolio. AMD just refreshed this unwritten law by positioning the six-core CPU at around $300. You can argue that this equals a 50% cost increase compared to the Phenom II X4, or decide between a mainstream Intel quad-core and AMD hexa-core CPU instead.

Optimizing Thuban

The six-core AMD portfolio is still very young and so far includes two models: the Phenom II X6 1090T at 3.2 GHz (up to 3.6 GHz Turbo CORE speed) and the Phenom II X6 1055T at 2.8 GHz (3.3 GHz max). The latter only costs $199, which makes the six-core story much more appealing for mainstream users with scalable workloads in their daily routine. We took the 3.2 GHz 1090T and overclocked it in 200 MHz increments to see how fast it can really go. From this, we determined the clock speed that delivers the highest performance per watt.

Display 17 Comments.
  • 1 Hide
    Enc0de , 14 June 2010 18:51
    What is the CPU cooler used in this test please?
  • 1 Hide
    Silmarunya , 14 June 2010 21:03
    Enc0deWhat is the CPU cooler used in this test please?


    Given I can see no mention of any cooler, I'd say they used the stock cooler, but voltage increases with stock cooling aren't something that happens often...
  • 1 Hide
    silverblue , 15 June 2010 01:24
    AMD may not be able to beat the Hyper-Threaded competition, but Thuban surely has the i5-750 beat when it comes to multithreaded workloads.
  • 2 Hide
    eriko , 15 June 2010 08:52
    Two things are clear from this investigation...
    1. The 980X is a very special chip, and at such a price.
    2. AMDs latest 6-core offering is incredible at $300. I'm no Fan-boi, but its nice to see some value out there...

    My 2c.
  • 1 Hide
    wild9 , 15 June 2010 09:23
    Upto 1/3 more performance than an AMD Phenom II x6 for 4x the price..yeah, Intel sure it leading the way..
  • 0 Hide
    wild9 , 15 June 2010 09:45
    I'd much rather run a Phenom II x6 at 3.6GHz, than a Phenom II x 4. Quite a testament to AMD's advancements in power efficiency, don't you think? Both chips are 45nm yet the x6 has two extra core's to take care of, but is still able to achieve similar idle draw as well as a respectable overclock. Spend a bit more on your cooling and see how high she can go.

    The results look good, and for this money I think they look like something of a real bargain. I'd take real more cores over threading units any day, even if Intel's cores are generally more efficient. The end result is what matters.
  • 2 Hide
    eriko , 15 June 2010 20:31
    @ Wild9 - if the 'end result' was the only consideration, then everyone would have the 980X.

    But what we have here is a bargin in terms of price/performance.
  • 0 Hide
    Anonymous , 16 June 2010 00:21
    Err... The only "conclusion" is that a maxed out overclocked and overvolted X6 can beat stock intels at the same price. One of the biggest points of the i5\i7 line is how easily they can crank out the overclocks; 3.6-3.8 is possible without overvolting on 'good' (D0\SLBJ) iX's, and a voltage bump in the 1.35v range will easily break 4.2-4.4 (though you'll be pushing the limits of air, especially if your still on a stock cooler).

    Redo the tests, but instead of using stock intel settings, try pushing them into the 4Ghz range where they belong and do a fair comparison. I've seen a 'good' i7 chip push into the 4.8 range on air, and 4.4-4.5 with a stock cooler and good ventilation. With even half decent scaling, it'll easily blow past the X6 in efficiency and price:p erformance.
  • 1 Hide
    openi3 , 16 June 2010 03:01
    Summary of article:
    Don't touch the core voltage, just increase multiplier/FSB for performance.
    For the latent thinkers:
    Don't touch the multiplier/FSB just undervolt.
    Option 1 should give better efficiency results in these tests but option 2 will give better results in a PC that's on all day and is asked to do a few demanding tasks with a fair bit of idle time.
    Power = VI^2 my friends.
    cb
  • 1 Hide
    Alfred_i , 16 June 2010 06:36
    overclocking i7 930 is better than x6 1090t.in photoshop and excel and gaming i7 @ stock is much better than 1090t.but question what happen if i7 930 overclocked?beat 1090t in another field or not?in this article you see efficently of overclocking 1090t and you can't say intel is better or not!!!for this they should overcclocked intel's cpu then compare with amd that they don't do that.
  • 1 Hide
    Anonymous , 16 June 2010 07:13
    AMD Phenom II stock coolers are actually pretty decent. Not entirely surprising if that was used.
  • 1 Hide
    wild9 , 16 June 2010 18:38
    ErikO@ Wild9 - if the 'end result' was the only consideration, then everyone would have the 980X.But what we have here is a bargin in terms of price/performance.


    For me the end result is that I can get good performance much less, even though I may have to use more core's to do it. The money I save would go on a killer GPU and a few TB of hard drive space.

    Can we bring Christmas a bit closer..? xD
  • 2 Hide
    Gonemad , 16 June 2010 19:50
    So, AMD squeezed lots of performance from a 45nm 6-core die, and did it for only $300. Give them the 32nm machinery, and see what happens. Is that a case of "Intel does it first, but AMD does it better or cheaper" again?
  • 0 Hide
    wild9 , 16 June 2010 22:28
    jimb0678AMD Phenom II stock coolers are actually pretty decent. Not entirely surprising if that was used.


    I agree. I have also had a good experience with their coolers, and it's nice to know that even if you're using a thermal pad you're still gonna get decent cooling and low noise. Can't say the say with regards to third-party coolers, even the more expensive one's.
  • 0 Hide
    Marcus52 , 22 June 2010 15:36
    AnonymousErr... The only "conclusion" is that a maxed out overclocked and overvolted X6 can beat stock intels at the same price. One of the biggest points of the i5\i7 line is how easily they can crank out the overclocks; 3.6-3.8 is possible without overvolting on 'good' (D0\SLBJ) iX's, and a voltage bump in the 1.35v range will easily break 4.2-4.4 (though you'll be pushing the limits of air, especially if your still on a stock cooler).Redo the tests, but instead of using stock intel settings, try pushing them into the 4Ghz range where they belong and do a fair comparison. I've seen a 'good' i7 chip push into the 4.8 range on air, and 4.4-4.5 with a stock cooler and good ventilation. With even half decent scaling, it'll easily blow past the X6 in efficiency and priceerformance.


    Of course you would be right if this article were a horsepower race - but that's not what it's about; it's about efficiency. Cranking the juice on the processors you talk about will require more power and will cause them to be less efficient.

    As far as your claims about an i7 going to 4.4-4.5 on the stock air cooler and 4.8 GHz on air - reporting what you've seen run long enough to take a CPU-Z snapshot of just before lockup is a bit dishonest. Post some Prime95 tested results - those are amazing enough.
  • 0 Hide
    sevyr , 4 August 2010 17:19
    GoneMadSo, AMD squeezed lots of performance from a 45nm 6-core die, and did it for only $300. Give them the 32nm machinery, and see what happens. Is that a case of "Intel does it first, but AMD does it better or cheaper" again?


    AMD is probably like: Intel, you can lead the way...we'll just clean up after your mess and reap the benefits ;) 
    OH YEAH!
  • 0 Hide
    silverblue , 4 August 2010 17:23
    I'm not sure it's reaping the benefits. Firstly, Turbo CORE is a less efficient implementation, and secondly, there's far more Intel i- CORE CPUs out there than Phenom IIs, but the Phenom II has won a lot of fans.
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