How to free up the memory in the best way

Question

I'm using Ubuntu 18.04 and 4GB RAM with CPU 4. I don't have too much memory left, so my computer works slowly and crashes. What would you recommend me to remove from directories? Or some command other than apt autoremove and apt autoclean because that's not enough. I have nothing to uninstall from the Ubuntu Software because there are only the most important things left. Please help :(

Solution 1

There's a couple things you can do. Some of them were already outlined in How can I improve Ubuntu overall system performance?. Here's a few simple suggestions you can try right now:

1. Switch to a lighter desktop, you don't need to reinstall, you could just install a desktop session such as xfce or install metapackage for another flavor, such as Xubuntu edition with sudo apt-get install xubuntu-desktop

2. Add more swap, either via partition or swap file. I've a script for adding swap files to make that process easier.

3. Configure swappiness to help the system handle memory-intensive apps. See also: SwapFaq

4. Disable certain services. Which services to disable will depend on your needs.

5. Buy more RAM. Make sure you buy modules with correct frequency and type.

6. Consider tuning resource usage for certain processes and niceness values
7. Consider some of the cleanup suggestions. BleachBit is a well-known and pretty good utility for that.

Solution 2

I'm just answering this old post to hopefully gain some reputation points... When dealing with low memory, I use this nifty little command to clean caches and buffers, saves me from having to use swap most of the time. I only have to use this command once every 2 or 3 days. I suppose this is what you're looking for?

free -h && sudo sysctl -w vm.drop_caches=3 && sudo sync && echo 3 | sudo tee /proc/sys/vm/drop_caches && free -h

Solution 3

Check real-time memory usage via the following commands:

watch -n 1 free -m
watch -n 1 cat /proc/meminfo

In returned outputs focus on Buffers, MemTotal, MemFree, Cached, Active, Inactive, etc,...

You can use the following command to free up memory either used or cached (page cache, inodes, and dentries):

sudo sync && echo 3 | sudo tee /proc/sys/vm/drop_caches***

Comments

[Bernard Wei]

4GB should be fine running Ubuntu 18.04. How much swap space are you using? And what applications are you seeiong the slow down? Try not to leave too many application running and avoid using Chrome browser, you'll be fine.

[David Foerster]

Possible duplicate of How do I find out which version and derivative of Ubuntu is right for my hardware in terms of minimal system requirements?

[Martin Thornton]

Do you mean disk space when you say memory?

[vidarlo]

Caches will be dropped automatically whenever applications ask for more memory. This will probably lead to an decrease in performance.