What is meaning of Silab clone?
If you click on the link above, you will see that somebody in India made a (lousy) copy of the Silabs dev board. Since Silabs publish the schematic of their dev boards (I wouldn't buy them if not) it can be very tempting, albeit probably illegal, to just make a copy.
HOWEVER, with the SILabs parts running at 100MHZ it takes more than a schematic to make it right and, as evident by the thread, whoever made the clone had nothing more than the schematic and could not even get that right.

I posted this for one reason only: to avoid anybody else spending good money on a non-performing product.

Erik