When loading chunks in creative mode flying around, all my cpu cores go to 100% and my game stutters a lot and my fps drops. I have my render distance set to 28 chunks, i can go up to 44. Preloaded chunks don't make my game lag, it's only when loading new chunks

System configuration: 

CPU: Core 2 quad q9650 quad core 3ghz

GPU: Nvidia Geforce GTX 960

RAM:8GB

Storage: 120GB SSD (both Minecraft and Windows are installed on it)

Latest drivers installed.

Minecraft java edition runs fine without optifine

I don't know why this happens, but it ruins the experience when flying around in creative mode.

Hope this will get fixed in the future.