From 2GB, the RAM available that is left for you to use is less. The rest is used by OS. If you want to divide, try 2*10^9 by 1024^3,you get a different memory,which is 1,86 on the device.
I don't know how you got that 1,86, but 1703MB is 1,66GB. So you mean that 0,33GB of RAM is occupied by the OS? Well, the relevant apps should show 2GB of RAM and the free available should exclude the amount occupied by OS and apps.
Just like from 16GB internal,you can use less. See if the same thing applies : 16*10^9(16 billion bytes that you get in the memory) which you need to divide by 1024^3 (how many bytes are actually in 1GB) and you get around 15. From there,OS and default apps take their part and you end up with about 12 GB.
I can't agree with you Alexdon: storage space is been sold (pure marketing) with metric values aka 1000MB is 1GB but RAM should still be 1024MB = 1GB I'm afraid your 2,150GHz ≈ 2,2GHz provides Vasilis and my answer though: 2GB looks much better in the specs than Vasilis's 1703MB or my 1695MB...
