Question RAM with different Module and DRAM manufacture?

[PeyoteFTW]

Just bought new ram and install it on second slot of my laptop, both is 2666mhz and ddr 4 with 8gb each capacity. But different module and dram manufacture.

Is it safe ?

 

[Unolocogringo]

Some times mixing modules works.
Some times they work but have very high latency.
Some times they work but have very low speed.
Some times they sort of work but stuttering ,occasional crashes happen. Word hangs. etc.....
But most of the time they don't work well together and the computer will not boot.
Can we see a picture of the memory tab to see what the memory is running at?