It's also a rather good marketing trick - pull people to the brand by providing the (remote) chance that you might actually get something better then you paid for. In the end, you're aware that ya buying a cheap chip, so won't/can't take it back if it doesn't unlock.

I seem to remember Intel actually frying the math coprocessor on some of their 486sx25 chips back in the past just to make quotas. Its not unheard of for chip makers to sell better parts for lower ones to meet sales. If you sell dell 2000 Celeron chips and don't have them in stock you have to fill that order. Sometimes they physically make them inoperable by running some current through the pins to fry them, but if you wait till the last minute to fill the order they might not have the time to go through each chip and disable them.

You can get a real Athlon II X2 for only $10 more. Until there's a wider price spread, this won't be very tempting.

What if someone tracks the lot numbers of the working 2-core semprons and post these numbers.

I am guessing other processor from the same lot number would be 2-core athlons and this would be a quick way to figure out the good processors.

of course they want to sell some good Athlon II X2 as disabled. That way they only need one process to produce the chip, cost a fortune to get another line of production. It doesnt hurt the price for Athlon II X2 and gains more in the market at the lower end. I don't see any reason not to do it.

the X2 doesn't sell it's that they're dirt cheap to mass produce.
You should be able to figure out the rest.

Well, if AMD only has 900 defective dual cores on hand to turn into single cores, they may have to cripple 100 effective dual cores to meet a batch of 1000 that, say, HP ordered.

Volume turns profits...if they need 1000 semps and have 800 , 200 X2s that might not sell take a hit and still make money.

... I fail to see why on earth would AMD choose to sell a perfectly good Athlon II X2 as a disabled, cheaper... chip. Quotas don't make the profit, you know...