Question 'K' series CPUs

So I know what a 'K' series CPU is. They have an unlocked multiplier, so they're the only way to go when you want a serious overclock.

My question is, how do they lock the multiplier on other CPU's? I'm not a cpu architecture guru, but isn't the multiplier controlled by the mobo, not the cpu? All the CPU's are cut from the same die, so how do some of them not allow multiplier changing?
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  1. It's on the chip itself. Someone can probably give a more technical explanation, but the chip is set to only operate at certain clock speeds and multipliers.

    I remember back in the day there were some physical mods you had to do to get the multiplier to change. It's fuzzy, but I think one even involved laying a new track with a graphite pencil! :)
  2. They probably have some machine that alters the chip at the intel factory
  3. Robi_g said:
    They probably have some machine that alters the chip at the intel factory

    Not really.

    The only difference between the 3570k, 3570, 3470, etc.... is how well the batch of chips are on the wafer. They just BIN all the wafers to see which name they would go under.

    They cherry pick the ones that has the most consistent structure and thus can handle the higher clock/overclocking and name them 3570k.

    If there is some degradation and they don't think that the batch will be able to handle the stress of overclocking and changing multipliers, they name them 3570.

    if there is more degradation and it can't even get to 3.4 ghz at a relative decent voltage/etc... then they name it 3470...

    if the chip can achieve the clock at lower core voltages, then it's the 3470s with the lower TDP.

    And no. there isn't a way to make a locked multiplier chip unlocked. in the current genertion I might add. because you could do it in several other older generations.
  4. It is likely a hardware lock in the CPU package after the CPU itself has been tested to determine how it will be binned.
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