On 32-bit versions of Ubuntu and other Linux systems, there is a limitation on the amount of RAM that the system can use. This limitation is typically around 4 GB, due to the fact that 32-bit systems can only address a maximum of 4 GB of physical memory.
If you are using a 32-bit version of Ubuntu and have more than 4 GB of RAM installed on your system, you may experience issues with the system being unable to access or use the additional RAM. This can result in reduced performance or other problems.
To address this issue, you can install a 64-bit version of Ubuntu or another Linux distribution. 64-bit systems can address much larger amounts of RAM (typically up to several terabytes) and do not have the 4 GB RAM limitation that 32-bit systems have.
To install a 64-bit version of Ubuntu, you will need to download the 64-bit installation image from the Ubuntu website and create a bootable USB drive or DVD. Then, you can boot from the installation media and follow the prompts to install the 64-bit version of Ubuntu on your system.
Keep in mind that in order to use a 64-bit version of Ubuntu, your computer must have a 64-bit processor and support hardware virtualization. You can check if your processor is 64-bit by running the lscpu command and looking for the Architecture field in the output. If the architecture is listed as x86_64, then your processor is 64-bit and you should be able to use a 64-bit version of Ubuntu.
Alternatively, you can use a memory management tool such as meminfo to try and optimize the use of RAM on your system. This may allow you to utilize more of your RAM and improve performance, even if you are using a 32-bit version of Ubuntu. However, this will not completely remove the 4 GB RAM limitation, and you may still experience issues if you have more than 4 GB of RAM installed on your system.