> unless they are currently using more that 0.2gb RAM for
> those devices and other such OS needs.

The difference between 2.0 GiB (= 2.15 GB) and 1.8 GB (= 1.68 GiB) is actually 0.35 GB (= 0.32 GiB).

> is an additional 0.3gb going to help?

The difference between 1.8 GB (= 1.68 GiB) and 1.5 GiB (= 1.61 GB) is actually 0.19 GB (= 0.18 GiB).