Motherboard is Asrock a320m-hdv r4.0, current ram is a kingston fury.
In the shop I could get kingston fury, g.skill aegis,corsair vengance, patriot viper and a few brands i never heard of. the listings go something like: Kingston Fury Beast, DDR4, 16 GB, 2666MHz, CL16.(my 2666MHz-4000MHz meant one could get any ram with frequency listed within this spectrum.)
I have no idea what MT/s speed, is but cpuz lists my "uncore frequency" as 1330MHz (I'm working with whatever i can see on the parts or whatever i can decipher from cpuz cause the boxes got lost in the attic)