Just went on Amazon. They removed the 9900K from the search results, and if you go to the page manually it says "currently unavailable". WTH is up!?
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Looks like confirmation this is an Intel paper launch to buy time until they can get production and yields up.
This is likely a super binned chip to pull off the clock speeds and power draw it achieves (quite good).
Amazon is usually pretty good about showing next incoming ship dates when supply orders come.
In this case, no updated ship date probably means no or limited supply coming any time soon.