The RAM isn't operating at its designed performance level.
The RAM isn't operating at its designed performance level.
I find it strange to revisit an old discussion, but I've invested a lot of time lately on this topic since I bought some new RAM and ran into the same issue. The specifications listed—clock speed, CAS latency, and voltage—are the factory settings used during testing. If the RAM passes those tests, they rate the module for use under current conditions. DDR4 stock speed is 2133MHz (or 1066.5 x2). This is the default BIOS setting if the system can't boot with new configurations. That means the numbers you see are overclock ratings that the maker claims the chip can handle stably. XMP generally works, and plugging in the manufacturer's values gets you there. But if the system doesn't boot with XMP enabled, you'll need to manually increase the RAM speed. When adjusting RAM speeds, keep in mind that CAS latency, clock rate, and voltage all affect stability. They must be balanced together for reliable performance.