While there is no single "189 fps boost mod" by that exact name, "189" typically refers to Minecraft version 1.8.9
Created by Skytils, this is widely considered the best mod for 1.8.9. It fixes hundreds of vanilla bugs and significantly improves performance without changing gameplay. 189 fps boost mod link
If you don't want to manage individual files, using a client like Lunar Client or Badlion Client essentially acts as an all-in-one FPS boost mod. They come pre-packaged with 1.8.9 optimizations. Essential Mods Included in the 189 Boost Pack While there is no single "189 fps boost
When searching for a download link, . The modding community is generally great, but third-party links can sometimes host malware. 189 fps boost mod link