Re: i bought 2x8gb ram set of the same size and speed  the spec speed is the same as Dell ram, but memory settings (latency etc.) is likely different from original Dell ram.  Thus Dell bios does not like the new ram, is not able to adjust itself to accommodate new ram settings in order to achieve spec speed, therefore Dell bios down clocks new ram to make it easier to work with.  happens all the time when user upgrades with non Dell ram.
I bought an OptiPlex 7060 tower a year or two ago and it came with 2x4gb ddr4 2666mhz ram and it worked just fine until i needed more , i bought 2x8gb ram set of the same size and speed , took out the 2 old ones and inserted the new ones but they were running at 2133mhz . I have been stressing over it for a day now and some professional help would be nice . Thank you
Why does my 2666mhz rams drop to 2133mhz ?