Is the RAM frequency lower than stated?

Question

motherboards

Hello, I have the following assembly:
Proc ryzen 5 2600
RAM 8 * 2 3000Hz.
What is the problem: after buying a PC, I immediately downloaded applications to check whether everything was working correctly, noticed that the RAM frequency was less than the declared one (2666), found on the Internet that this was due to sdr, it should be 2 times lower than the declared one, but it is only 334 is smaller and in cpu-z it shows sdr in brackets. Then I went into the BIOS, but the real frequency is 2666, I decided to set 3000 manually, but I'm a little worried if I did everything right. Who knows, please tell me what this is connected with, and what should I do?