Both the Athlon II X2 and the Phenom II X2 managed to overclock to about the same levels. Without any additional core voltage they were able to run at 3.5 - 3.6GHz, with the Athlon II being able to go a bit higher thanks to being free of any L3 cache. With less than 10% additional core voltage I was able to get both chips up to 3.7GHz. The Athlon II X2 250, when overvolted, managed to reliably hit 3.75GHz.

Gary's sample was able to work solid at 4.0GHz while mine would fail at 3.8GHz or above.

Processor Highest Overclock (Stock Voltage) Highest Overclock (Overvolted) % Increase over stock
AMD Phenom II X2 550 BE 3.5GHz 3.7GHz 19%
AMD Athlon II X2 250 3.6GHz 3.75GHz 25%
Intel Pentium E6300 3.40GHz 3.57GHz 28%


The Pentium E6300 topped out just under 3.6GHz with ~10% additional voltage. I noticed a strange trend when overclocking the E6300. I set the FSB to 340MHz, which when multiplied with the CPU's 10.5x multiplier should yield 3.57GHz. Yet with no additional voltage, the CPU would hardly ever go above a 10.0x multiplier once in Windows - resulting in a 3.40GHz clock speed:

The chip wasn't throttling due to heat, it simply would not run at 3.57GHz without any additional voltage. As soon as I gave it more voltage or as soon as I disabled EIST, the CPU ran at its correct frequency:

All I did was disable EIST, although increasing the VID also resulted in the same thing

Even with additional voltage however I wasn't able to get the E6300 stable at above 3.57GHz.

Processor x264 Pass 2 Cinebench XCPU Crysis Warhead
AMD Phenom II X2 550 BE @ 3.7GHz 11.0 fps 8224 74.5 fps
AMD Athlon II X2 250 @ 3.75GHz 11.0 fps 7968 75.0 fps
Intel Pentium E6300 @ 3.57GHz 11.7 fps 8096 80.8 fps


The Pentium E6300 is actually quite competitive when overclocked and appears to scale very well with additional clock speed. It also helps that AMD's clock speed advantage shrinks once we overclock these chips a bit.

Power Consumption Final Words
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  • Gary Key - Tuesday, June 2, 2009 - link

    The X2 6400+ is in the charts now and you can always use our Bench tool to compare a whole litany of processors against each other. AMD is currently phasing out of 90nm production and even several 65nm products will be phased out this year as they ramp the 45nm production.
  • Spoelie - Thursday, June 4, 2009 - link

    WOW, it really amazes me how little performance has improved. Athlon II X2 750 (3ghz) is barely faster in most benchmarks than a Athlon X2 6400+ (3,2ghz), and loses in 1 or 2.

    So the phenom core redesign buys around 300mhz around 3ghz, or only 10%. Everything else that improved in phenom is uncore.

    And this while the original is at 90nm and the new one is 45nm, what a waste of potential. It seems to me AMD could've tried a little harder with the Athlon II.
  • Spoelie - Tuesday, June 2, 2009 - link

    There's a small util/service out there that brings phenom II cnq behaviour from vista over to windows xp (phenom II's cnq behaves like phenom I's cnq under windows xp). It does this by disabling standard cnq (set power management not on "minimal") and implementing pstate changing itself


    Maybe it can do the same for the Athlon II X2 on vista...
  • mohindar - Tuesday, June 2, 2009 - link

    Hello Anand,

    It will be very nice to provide some benches regarding desktop virtualization, like how windows-xp usage on this chip and so on...
  • plonk420 - Tuesday, June 2, 2009 - link

    i'm curious to see this on the bench!
  • mapesdhs - Tuesday, June 2, 2009 - link

    I'm beginning to wonder whether AMD/Intel are making the same mistake
    we saw last year with gfx cards, ie. too many different options. What
    is the target market for the new AMD CPUs? Many retailers seem to
    offer just a small selection.

    Any chance you could add an i7 920 and a 6000+ to the tables please?
    The former for completeness, the latter to show how the newer AMD
    parts stack up against a typical older product. I'd been hoping for
    a suitable replacement for the 6000+ in my ASUS board, but still nothing (no BIOS support).

    Atm it looks like my next system will be an i7 920 setup (core task
    is video encoding). In the past there's been lots of talk about the
    higher cost of an i7 system, but looking around yesterday, I was
    surprised at how small the difference has now become. The i7 920 is
    only 18% more than the Ph2 955 BE. Expecting a larger difference for
    the mbd cost, I found an X58 board from Gigabyte (the GA-EX58-UD3R,
    135 UKP from LambdaTek) right in the middle of the price range of
    typical AM3 boards. They both use DDR3, so that isn't a factor. I
    was going to build a Ph2 955 BE system for my brother as his next
    gaming rig, but with such small price differences now in play, the
    i7 looks more sensible.

    Oh, a typo on the first page perhaps? Surely it should be 2 cores for
    the Athlon64 X2?


  • smilingcrow - Tuesday, June 2, 2009 - link

    Judging by other reviews your choice of using the x264 HD Bench Pass 1 for the Power Consumption comparison doesn’t give a true representation of the situation.
    As expected other reviews shows the Athlon II X2 having a noticeably lower power consumption under typical loads.

    The Phenom II X2 has too much extra circuitry to have lower power consumption and I’m surprised that you didn’t deduce that something was amiss.
  • Anand Lal Shimpi - Tuesday, June 2, 2009 - link

    As I mentioned on the power consumption page, I'm guessing it has more to do with the current level of BIOS support for the Athlon II's power management. AMD is expecting a much better situation in the coming weeks.

    Take care,
  • Eeqmcsq - Tuesday, June 2, 2009 - link

    The one comparing various Athlon X2 specs. The table says the Athlon 64 X2 has 4 cores.
  • Anand Lal Shimpi - Tuesday, June 2, 2009 - link

    Woops, thank you :)


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