@StarRunner 

Hi,

Please have a look at this article: https://www.tp-link.com/en/support/faq/2928/

By the way, an actual data throughput of 300 Mbps over a meaningful distance can be considered as very good for an "AV2000"-rated Powerline adapter.

  @woozle read the article. So in other words, the advertised speed written on boxes is to mislead ppl? That is very disappointing.

  @StarRunner 

I agree it is misleading. However, Powerline adapters for home use have been around for more than 15 years already and it has always been the case that all manufacturers advertise the maximum signal rate of the product, while the practically achievable data transfer speed has always been just a small fraction of that advertised number. So it has basically become the norm.