RX 470 Mining Problem

I’m mining using a ROG STRIX-RX470-O4G-GAMING using multiminer 4.1.0. The problem is, when I’m mining, the current hashrate reads 20-24 kh/s, but the effective hashrate goes down way below that number. When I check on the website of the server I use which tracks shares and hashrate, it gives a similar answer. Am I doing something wrong or is this normal?