Question Windows 10 not detecting all ram slots

[Venc2469]

I have a new laptop with 4gb ram, Ryzen 2500u 120gb ssd, and I have two questions really:

first one windows is reporting that the ram is running at 1333mhz which is very low for ddr4, and secondly:

Windows shows that the pc only has one ram slot available, wich would be fine but when I opened it, it had two slots, will it work when I put another stick in it?

 

[rgd1101]

ddr4 is double rated. 1333 is 2666.
exact model of this laptop?

 

[Venc2469]

ddr4 is double rated. 1333 is 2666.
exact model of this laptop?

Acer aspire 315 r28w I think, it says it has only one slot but it has two
It's a a315-41-R26W

 

[Venc2469]

I put in another stick of 4gb ram from Lenovo that I had laying around (it's rated at 2133mhz)
Windows still reports the ram as running at 1333mhz but the performance jump is decent enough

 

[Prostar Computer]

1333MHz is the clock rate. 2666 is the transfers per second, or sample rate. Memory often gets advertised using the bigger number (2666MHz, for example), while software will usually show you the clock rate instead of the sample rate.

Yes, you can install memory in any available bank. Ideally, you want to match the make, model, and capacity of each stick, but you can get away with mixing things (usually).