Speed of memory storage
Speed of memory storage
It's possible the wrong speed was selected in the BIOS, so you may need to adjust it to XMP.
Use the Memory section to view real performance. Multiply your RAM clock speed by two to determine the actual speed it operates at.
The physical speed listed by CPU-Z matches the 2667 MT/s rating. It reflects the actual data bus rate, not a single channel issue. Everything is functioning properly.