Low FPS

Windows and your PC

1. Use the right graphics card. On a laptop with two GPUs, Windows often runs games on the weak built-in one. Open Windows Settings, System, Display, Graphics, add Sour Client's Java (the javaw.exe under %USERPROFILE%\SourClientData\runtimes) and set it to High performance.
2. Plug the laptop in and set Windows' power mode to Best performance. On battery, most laptops cut the GPU's speed hard.
3. Update your graphics drivers from NVIDIA, AMD or Intel.
4. Close heavy background apps: browsers with many tabs, recording software you are not using, game launchers downloading updates.

In Sour Client

1. Set FPS Performance Mode to Balanced or Extreme (what each does).
2. Turn on Run on Java 21 for your 1.8.9 profile (how). Most PCs get more frames and fewer stutters.
3. In crowded lobbies, Entity Render Distance stops drawing distant entities.
4. Lower Particles, and turn off Motion Blur and menu blur if you do not need them.
5. Check the HUD: dozens of widgets on Quality mode redraw 240 times a second. HUD Refresh Rate can lower that.

Minecraft's own settings

• Render distance: 8 to 12 chunks is plenty for PvP. It is the biggest single setting.
• OptiFine: Fast graphics, Smooth Lighting off or low, Render Regions on, Smooth FPS off. Sour sets the last two for you once.
• Max framerate: Unlimited with VSync off, unless your screen tears and you prefer VSync.
• Shaders cost more than everything else combined. Turn them off to test.

Memory

Set the profile's memory to 3 or 4 GB. More is not faster: past what the game needs, it only makes memory clean-ups longer.