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Unlocking AMD CPU Cores Safe Say Mobo Makers

While browsing through motherboards at Computex, several manufacturers were quick to tell us some details about the recently released dual-core Phenom II CPUs from AMD.

Two motherboard makers told us at the show that AMD's new processors are safe when unlocking disabled cores. In fact, one motherboard maker even told us that when you unlock the disabled cores, they run at slower frequencies than the normal cores.

This is of course all incorrect, and it is indeed not a safe guarantee when you unlock the disabled cores. The reason for this is that the disabled cores are turned off for a reason: they failed factory tests. Cores can fail for any number of reasons, including defects in the silicon, problems running at full frequency, or a bug introduced during manufacturing.

Both AMD and Intel disable CPU cores for this very reason.

When you unlock the disabled cores, they will run at full processor frequency, since you cannot run each core at different speeds. While you may see initial gains and benefits from turning a dual-core CPU into a quad-core CPU, you may introduce instability into your system. Things may corrupt, calculate incorrectly or even crash.

Despite what we were told, we still recommend that if you're going to unlock disabled cores, do so with caution in mind--there is always a risk that something will go wrong.

  • tweak13
    Wait what, I had no idea there were disabled (extra) cores in cpu's.
    Reply
  • hunter315
    All of the Phenom II's are identical designs, the best ones end up as 955s and the defective ones end up as 8xx X4s, 7xx X3s, and 5xx X2s. So you only have disabled cores if you bought a phenom. I dont know which Intels have disabled cores.
    Reply
  • tweak13
    hunter315All of the Phenom II's are identical designs, the best ones end up as 955s and the defective ones end up as 8xx X4s, 7xx X3s, and 5xx X2s. So you only have disabled cores if you bought a phenom. I dont know which Intels have disabled cores.
    very interesting, thanks.
    Reply
  • Hanin33
    tweak13Wait what, I had no idea there were disabled (extra) cores in cpu's.
    there are in some tri and dual core chips since they are often rebinned quads that failed QA testing. tho i think AMD doesn't put out many if any dual cores that were once quads since they use a real dual core/single die unlike wot intel did with core2.
    Reply
  • w4ffles
    I'd like to know where those representatives got their "facts".

    AMD disables cores and sells them in a lower segment because it's more financially sound than just tossing them out.

    I've never heard of Intel disabling cores, but I wouldn't be surprised if some of the dual-core CPUs were like that.
    Reply
  • edeawillrule
    What Intel does is use dual core chips that have a defective core as single core celerons. Also in the case of core solo chips (Core 2 Solo chips I'm not sure about) they were dual core with one core disabled.
    Reply
  • kingnoobe
    I can't see why intel wouldn't. It makes perfect business sense. To simply disable the faulty cores, when the others are perfectly fine.
    Reply
  • dextermat
    is that why clients that got quad cores got random BSOD for no reasons....

    Intel and AMD still has to straiten things out on thoses quads
    Reply
  • ThisIsMe
    Intel wouldn't because they do not use a true quad core chip. It's actually two dual core chips. They couldn't disable a core from one dual core set and disable another core from the other dual core set because it wouldn't make sense from a performance standpoint.

    If they disabled both cores from one dual core side I guess that would work, but would be horribly inefficient, unless they only used this for one specific model and made the rest regular dual cores.
    Reply
  • scooterlibby
    Anand said this loophole will close fast (BIOS updates, clearing of inventory with stable 3rd and 4th cores), so you have to get a Phenom II X2 very soon and make sure you have a mobo with a BIOS that can still unlock. Even then it's not guaranteed to be stable, but I say go for it if you can pull the trigger now and know you're getting the right mobo.
    Reply