Many thanks for your reply...
i will upgrade to 2133mhz in the near future,
then i will report my findings..
Update..
I purchased an additional 4GB of DDR-4 2133mhz , a week ago...
Now my laptop runs flawlessly....
In short.. this model cannot run 2 sticks of RAM, with 2 different frequencies...
This laptop has 4GB 2133mhz soldered onto the motherboard, so a purchase of additional
RAM, for the one remaining slot is restricted to RAM of 2133mhz only...
Thanks to everyone who has advised and contributed, in this thread, and the previous
thread..
Mike...