So im guessing that flare x are samsung b-die and amd compatible also i think that they are dual rank so they wont lack so much speed and i will have for the same price another 16gb wont i? Thank you for ur responses.
Depends on what purpose. If you are into running VM's and production work, the 32Gb will be far better overall than the 16Gb, no matter the speed differences to Ryzen. If for gaming, then Ryzens love faster ram, they make far better use of it than Intel as it goes hand in hand with thread bandwidth. So in that case, the 16Gb of 3200 can show upto @20% better fps than the 32Gb of 2400.
Even running high ram usage games with 2080ti sli at 4k will barely see total ram usage beyond 12Gb, so 16Gb is more than enough for any gaming orientated pc.
There's only 1 way to see quad channel usage, and thats on a mobo capable of running quad channel. That means TR4 or x99/299 type enthusiast boards with 8 ram slots. Any consumer class mobo using Ryzen or Intel with only 2-4 ram slots only has dual channel capability.
And 1 specific video on 1 specific test doesn't cover all the results. There's plenty of other tests/reviews that show for the most part there's no difference between dual and quad channel performance, the only benefit to quad channel being double the bandwidth. If you can't saturate the bandwidth of regular dual channel, any excess size is moot and not used.