Imagine you are AMD employee responsible for creating this slide and you know Zen 3 has SMT4. Your goal is to avoid disclose SMT4 and other significant uarch changes because it is planned to be revealed on spring 2020. So lets assume that disclosing Zen3 SMT4 breakthrough feature during Zen2 presentation is not good idea.
What would you put there? You have simply two options:
- - leave it empty (this would mean there is something hidden and provoke even bigger speculations)
- - put "2X" (knowing SMT4 CPU can run at SMT2 mode too, so you are not technicaly lying and keeps uarch secrets hidden until oficial Zen3 presentation)
Most people was predicting small changes for Zen3 (something like Zen2+ was expected) which exclude SMT4 (I agree, that's logical and I understand why most people didn't beleive those SMT4 speculations). However now when AMD confirmed Zen3 is completely new uarch things changed up side down. New uarch means opportunity for feature set expansion (6xALUs, SMT4, AVX512 half speed) as a solid base for future iterations of Zen4 and 5. This slide proves that Zen3 will be SMT2 capable but not excluding SMT4.
Saying Zen3 has no SMT4 feature for 100% is very extreme opinion (only AMD engineers can say this, silicon matters not letters at some slide).
I'm more Heinrich Schliemann type of guy. He admitted the myth about Troy to be truth and following this he actually found the lost city.