RFID readers can read numerous tags within a second. The speed of processing the data is limited and it depends on database and network. The rate of reading is affected by the amount of data in the tag. Backend processing, middleware and management reporting procedures should be matched with the tags and readers.
The speed varies since a big amount of data is produced by the RFID system. If you are implementing this system, avoid direct hooking of the readers to the ERP system and backend management. By searching on the Internet by the keyword RFID chip timing Denton Texas, you will get sufficient information on the topic.