My ram is not running at advertised speeds

[Tuned]

I have a hp pavilion gaming desktop 690-0073w and I upgraded the one stick of 8gb ram to 2 sticks of 8gb of ram, the ram is called G.skill 8GB Ripjawz V series DDR4. Now originally the 8gb stick that came with this pc was running at 2666mhz now that I upgraded now the ram is running at 2133mhz is there any way I can change the speed back to 2666mhz?

[TheOldMan]

I was taught that when adding RAM that it should be done with matched pairs.  In other words if more than one memory stick is used, they need to be identical.  While the PC will make accommodations when the memory does not match,  so it will run, something like what you noticed will happen.

I would recommend either looking at the memory that was from the factory and match that, same make and model number, etc.  Or get a matched pair of new memory.  Something between the new memory and the old memory is preventing the speed to match what it was before, because of a mismatch in spec's.

Now to the question - few OEM's give the option to change the memory speed, but if it was possible, it would be in the BIOS settings.

[Tuned]

Both ram sticks are identical that I installed and I looked into bios but I cant find any settings like xmp to fix it

[TheOldMan]

As noted above, the motherboard and CPU come to an arrangement where the system will run.  Since both memory slots might just  align to run at a lower speed that what the single stick was running.  And MOST OEM  BIOS's do not give the user the option to change the memory speed. OEM's are more inclined to not give the user too many options, therefore the system will run properly.  

If you feel compelled to change the memory speed, then changing to a retail motherboard will probably give that option in the BIOS, but it might also fail to run ideally, or not at all at a different speed.

Where did the impression of the original premise that the "advertised speed" is 2666mhz come from, anyways?