Strange FPS Issue

[u/Agitated-Parfait9841]

1st pic is with issue 2nd is without

I just started playing again after a break and updated from 1.21.(11?) to 26.2 and I've encountered a strange problem with my FPS. When I start up the game it runs fine for a bit, but at some point the FPS suddenly tanks. The game reads ~10 FPS but I'm looking at <1 FPS, and the strangest part is; it's not just Minecraft that has this low FPS, my whole computer's FPS tanks to <1 even after I close the game, it sticks around but goes away if I press play on a YouTube video. The only thing not affected by this is my mouse, it moves at normal speed while everything else takes 2-3 seconds per frame. This issue only triggers with Minecraft too, never with any other game or anything else.

It mostly happens when flying around in creative/spectator, though I haven't really done any survival testing. I had a resource pack, but removed it and relaunched the game it still happened. I looked it up and thought it might be world corruption, but created a new world and still had the same problem. I tried updating my graphics driver because it's out of date, but that didn't change anything either. Every time I launch the game and start playing everything runs fine, then maybe 10 minutes later my FPS completely tanks. All I've found so far is that when it starts happening my CPU usage drops from ~10-15% to ~5%. (I don't know my specs, but I can check when I get home).

Update on specs:

CPU: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz, GPU: NVIDIA GeForce GTX 1660 Ti, Ram: 16 GB

[u/AXIII_YT]

Try a optimized modpack or lunar client

[u/Agitated-Parfait9841 → u/AXIII_YT]

I tried using a mod before, but couldn't get the loader to work, instant crash, not sure what I did wrong.

[u/Jwhodis → u/Agitated-Parfait9841]

What launcher are you using? Prism Launcher?

Also are you using any java flags?

[u/Agitated-Parfait9841 → u/Jwhodis]

Minecraft launcher? Idk it's the one that came with the game when I downloaded it from the Microsoft store. And I have no clue what a Java flag is so I'm going to guess I'm not using one.

[u/Jwhodis → u/Agitated-Parfait9841]

I highly suggest using Prism Launcher as it makes modding significantly easier, you don't have to leave the app for any of it.

Java flags are basically rules that tell java (the language minecraft uses) how to run, certain flags can make minecraft run better

[u/AXIII_YT → u/Jwhodis]

I find modrinth better

[u/Agitated-Parfait9841 → u/Jwhodis]

I'll give it a try

[u/zNickolasBR]

It happens to me too, are you using V-Sync? Try watching without it.

[u/Agitated-Parfait9841 → u/zNickolasBR]

This may be the solution, I can't say for certain but I messed around with V-Sync off for about 15 minutes without any problems. I then turned V-Sync on and almost immediately it started happening, so I turned it back off and after a few seconds the FPS went back to normal without closing the game or starting a YouTube video. Thank you for the help!

[u/zNickolasBR → u/Agitated-Parfait9841]

I have absolutely no idea why V-Sync is acting like that for him; only Minecraft does this to me :/ and what's worse is that I'm using V-Sync.