Thanks. My familiarity with the internals of PCs is not at a great level. It’s why I bought a pre-built, even though I know it would probably have been better to try to build one myself; however, I have short attention span when it comes to DIY projects and a lot of time they remain unfinished. 
The Lenovo uses the Z790 chipset. I looked that up and it said the chipset can support higher speeds, but who knows whether Lenovo’s MB can, even if it does use that chipset. There is no QVL for their boards. I’m not even sure if the voltage level for the RAM can be varied. The RAM in there now appears to be using 1.10 Volts according to documentation I could find on it. The new RAM uses 1.4 V.