Newegg sent out marketing emails at 2:33am today in which they promo'd Intel's much anticipated i9 9900KS & surprisingly within hours the processor was sold out. The i9 9900KS (S for Special Edition) are 9900K's that have been specially selected & tested to be able to achieve 5.0GHz on all cores in a 24/7 environment. Early tests have been fruitful with several users able to achieve over 5GHz & have the processor be stable using only air.
Intel was said to begin selling the processor in early October, but so far only one foreign outlet has been confirmed to have had a listing. That listing was quickly taken down as there appeared to be a pricing error, still one lucky user received his processor & posted the results on Reddit.
The CPU does still look to be packaged with several motherboards on Newegg which include MSI's MEG Z390 GODLIKE, ASRock's Z390 Phantom Gaming X, Asus' ROG Maximus XI Apex & Gigabyte's Z390 Aorus Master.
You can find Newegg's i9-9900KS listing here