Sodium & Iris (Fabric) VS Sodium & Iris (Forge) 1.18.2 FPS Comparison
Video source: https://youtu.be/Ve3I5gS6WGI
Make sure you are running the latest version of Fabric and Forge for 1.18.2 to get the mods running smoothly.
For fabric you will also need Mod Menu to see the Mods button. Grab it Here
You will also need a FPS counter mod. Get FPS Reducer mod (dont worry it doesnt reduce actual game fps) and make sure you enable the HUD settings in the mod's config settings. Grab it Here (view the file name to see which version you are getting)
I would recommend using an external app to measure your true FPS. Read Here on which app to get. Also never use the F3 console to see your FPS as it shows a lower amount.
You can now decide which version of Sodium and Iris Shaders you need to get
(Forge) Iris Shaders (Oculus) - Here
Get the Prismarine Shaders from Here