No pre-orders that I know of, and I've been searching.
13900KS should launch today or tomorrow. Been researching the 12900KS and some enthusiasts saying stock idle thermals are high like 45C 50C, for no apparent reason other than - that's the way the 12900KS runs. If that's the case with the 13900KS, I'll probably return mine for refund and grab a 13900KF.
With that in mind, I'm not able to buy from Newegg, they have no CPU refund policy... If Newegg offered "return for store credit" that would be fine, but I couldn't find that option.
Newegg - return for replacement only - NO refunds.
Best Buy - 15days full refund or replacement
Amazon US - 30days full refund or replacement
https://videocardz.com/newz/intel-shows-off-core-i9-13900ks-cpu-running-6-ghz-out-of-the-box
Z790 Epiphenomenal Raptor Bench
ROG Z790 Apex / Intel 13900KS SP111 P121 E93 MC83
Gskill 8000 kit - TM5 stable at 8200MT/s 38 48 48 121 VDD and VDDQ 1.5v
WD_Black SN850X 1TB 7300MB/s Reads 6300MB/s Writes
LG 32in 4K IPS 32UP83A-W