From your screenshot it looks like the system is using 1.7 GiB from 7.7 GiB
To me that doesn’t look bad.
The freezing can be caused by something else tho: baloo indexing, schedulers …
Do you have a SSD and a swap partition on it? Maybe better approach is a swapfile or systemd-swap.
Please provide more information about your system, as pointed out here:
