On April 12th, just shortly after the release of the 14th Gen Core processors, the 13th Gen Core CPUs have already begun their phase-out process, starting with the boxed K series overclockable versions.
According to Intel's announcement, the boxed versions of i5-13600K/KF, i7-13700K/KF, and i9-13900K/KF/KS have all entered the process of being discontinued. After May 24th, no new orders will be accepted, and orders already placed cannot be canceled or returned. Shipments will cease after June 28th.
Completing the entire process in less than two months is exceptionally swift compared to the usual one to two-year cycle.
Of course, these products will continue to be sold for a while, and individual components will be available for a long time.
In fact, you can still buy the 12th generation Core i9 K-series processors.
As for why the 13th generation Core i9 K-series is being retired so quickly, it may be because the 14th generation Core i9 K-series is too similar to it, with just differences in frequency.
