Cool story brah.. Since when is overclocking a part of TDP?
Of course O/C will go way way above TDP that's the whole idea.
It matters because most every motherboard out there will apply an "overclock" automatically to the i9 9900K. If you just put the processor in, load bios to set your RAM profile and touch nothing else the vast majority of boards will automatically have the processor running in an overclocked state. Saying that motherboard partners are doing this makes the processor's reported TDP even more meaningless. I can see the argument that OEMs pushing out pre-built systems may follow the TDP and limit the clock speeds, but for anyone building their own rig and just loading into windows you'll have an automatic overclock applied. If you built your system looking at the TDP (and were planning to run at stock) for deciding their cooling solution Intel's TDP is totally meaningless. This isn't new news and has been covered by most reviewers by the way. If you buy a cooler to dissipate 125W of heat plug in a 10900K and figure you'll be fine your in for a lot of thermal throttling. Even the 10900 (non K) will draw much more power than 65W and will require a cooler that can dissipate more than 65W which is why the TDP rating is meaningless.
Intel isn't alone in this as AMDs TDPs are also deceptive. My 3800X at stock will typically draw less than 105W, and with my 4.5Ghz all core overclock is probably drawing ~160W (torture testing), but the R7 3700X can draw more than its rated 65W even at stock. AMD's TDP is closer to an actual TDP than Intel but neither actually give the real picture. Intel is hands down the worst offender of this though as the 9900K at stock can draw around 200W during Prime 95 torture testing which is much higher than its 95W TDP.
My bad for the 300W quote for the 9900K. I didn't proof read enough before the post. I was thinking of the 10900 series at 300W+, the 9900K(S) will typically draw around 250W overclocked and under Prime 95 torture testing.
As far as TDP goes, I would like to see an industry standard set that both AMD and Intel have to follow rather than have both companies play fast and loose with their TDP ratings. Right now Intel tends to be a worse offender of skewing these figures but both companies are guilty of skewing the numbers to look better. There isn't any reason to believe that at some point AMD might really fudge its numbers badly too. There should be an industry standard so neither can get away with it.
My other points are totally irrefutable though. The 9900KS can easily hit 5.1, 5.2Ghz all core which means it will have the same (possibly better) gaming performance of the upcoming 10900 series. In productivity based applications the extra cores and clock speed of the 10900 series won't mean anything with Zen 3 launching in June / July. The 10900 series is a place holder because Intel was once again unable to bring high end desktop 10nm chips to market.