If you don't know how much RAM you can allocate, you can right-click This PC/My computer on the file explorer, click on Properties, and one of the information is the amount of RAM available, use something less than that. Remember to not set it higher than your computer can handle, RAM is still needed for background tasks and the Operational System. Change the 2 to the amount of RAM you want to allocate for Minecraft, for example: -Xmx4G for 4GB RAM, -Xmx8G for 8GB RAM, and so on.Where it says ' JVM ARGUMENTS', at the start there are the letters: -Xmx2G.On the Minecraft Launcher, click on the Installations tab and edit the installation you'll increase RAM for.This is a quick change that can improve performance a lot, by default your game will allocate up to 2GB RAM, this is a very low amount for some systems, if you have spare RAM, consider raising this value. If you get the Java runtime incompatible error, then you are using the wrong version, remember to use OpenJ9 16 for Minecraft 1.17+ or OpenJ9 8 otherwise. If you get the Java version mismatch error after installing and setting OpenJ9, it is because you selected the bin folder javaw.exe instead of the one inside the jre and then bin folder, change the path in your installation settings and try again. If you play multiple Minecraft versions and you want to set OpenJ9 for all of them, just download both versions 8 and 16 and change the path for the installation accordingly. If you feel like OpenJ9 didn't help you, just remove the path from the installation settings. Hover with your mouse on the Minecraft installation you want to change to OpenJ9 and click on the three dots icon on the right, and Edit.Note how when downloading from Adopt Open JDK, the OpenJ9 option has to be checked. If you're playing Minecraft 1.17.x+, download the OpenJ9 version 16, otherwise, download the OpenJ9 version 8. You can download and install OpenJ9 from Adopt Open JDK, but the version will change depending on your Minecraft version.Hotspot, the default one is also a great JVM, that's why it's good to do your tests. The Java Virtual Machine (JVM) plays an important role in running Minecraft, defining how work is done under the hood. Have you heard about OpenJ9? OpenJ9 is a Java Virtual Machine implementation, used to run Minecraft, it is reportedly faster to run Minecraft on OpenJ9 than on Hotspot.

Low FPS occasionally happens if you're using too many mods, an expensive shader, or have a low-end computer. It can be a great idea to attempt to improve Minecraft performance if you're running with low frames per second.

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