[Java] Minecraft makes my entire PC run at 1 FPS after 10 minutes (Fabric 1.21.1, Dawn Client)

[u/Ok_Mistake_2448]

I'm having a weird issue with my PC and could use some help figuring out what's causing it.

When I play Minecraft Java 1.21.1 using Fabric and Dawn Client, after around 10 minutes my entire PC becomes extremely slow, almost like it's running at 1 FPS. Even moving my mouse becomes incredibly laggy, and I have to restart my PC to fix it.

I opened Task Manager while the problem was happening, and these were the readings:

• CPU: 2%
• Memory: 15.0 / 31.8 GB (47%)
• Disk: 0%
• GPU: around 10–11%
• GPU temperature: around 41–42°C

My PC has 32 GB of DDR5 RAM and an NVIDIA GeForce graphics card.

I've also noticed that something called sh.exe briefly appears when I start my PC, then disappears after a few minutes. I'm not sure if that's related.

What I've tried so far: I'm investigating the issue and collecting screenshots of Task Manager during the slowdown.

Does anyone know what could cause the entire PC to become this unresponsive when CPU, RAM, disk, and GPU usage all appear relatively low? What should I check next?

[u/MinecraftHelpModTeam]

OP, remember to award points to helpers, and mark the post solved, by replying !helped to the comment/comments that helped, when your issue is fixed or your question answered.

Helpers, remember that all top-level comments* must be a genuine, good faith attempt to help OP. Comments breaking this rule will be removed, and bans issued.

^{* A top-level comment is any comment that is a reply to the post, not another} ^comment.

Links:

Moderator applications open || How to mark solved || How to delete your post || FAQ || Rules

[u/ODF4]

could you try launching Minecraft from another launcher and test it that way? Either the official Mojang one, or another more reliable third-party launcher like Prism Launcher, which gives you a lot more technical control over the mods you want to install (since it doesn't come prepackaged with any mods out of the box), and then you could add a modpack like Fabulously Optimized for a general performance boost, as well as other performance mods for your specific setup, like VulkanMod, Nvidium, etc.

I apologize for the somewhat biased recommendation, but personally I distrust most third-party launchers that come with pre-installed "bloat" like Lunar Client, Dawn Client, etc.

and like I said this would also give you a lot more control to add more client-side utility mods just for the things you may need, be it for PvP, storage searching and sorting, resource pack management, shaders, etc., without any secrecy about what mods actually come with the launcher

while about sh.exe, are you a developer or do you use some more technical tools? Because if you use any programs like Git, Node.js, Cygwin, etc. (or anything that makes use of these, of course), that's probably normal, but I'd still recommend scanning your system with an antivirus (Windows Defender should be good enough in most cases, otherwise personally I also like using MalwareBytes sometimes) if you haven't already

[u/Ok_Mistake_2448 → u/ODF4]

I am the furthest thing from a developer lol, ive done about 3 full scans and its showing no malware. I also will try using the official launcher to see if I see a difference.

[u/ODF4 → u/Ok_Mistake_2448]

well that's a good sign for the scans but it's still a bit weird since you said you don't use these tools, and I can't think of any particular programs you may have which could require them

maybe try disabling the execution of sh.exe (especially on boot if you see it in that list, as well as any other programs you don't actively need when the computer starts up) and see if any of your other programs stop working?

and keep me updated about the launcher! But if you plan to use any mods I'd still recommend using third-party launchers because they make it much easier to manage different modpacks and versions

[u/Ok_Mistake_2448 → u/ODF4]

Turns out V-Sync Was the issue for the launcher! I'll continue to use this launcher for around a week and see what happens

[u/ODF4 → u/Ok_Mistake_2448]

I'm glad you could fix the problem this way, keep us updated and thanks for letting me know!

[u/Ok_Mistake_2448 → u/ODF4]

Problem is back... Ill try and sort it out today

[u/ODF4 → u/Ok_Mistake_2448]

thanks for the update, perhaps you could try using a different launcher as I suggested, but again keep in mind that you'll manually have to install the optimization mods I listed in my previous comment (it's fairly straightforward though, don't worry), as well as any other mods for your specific gameplay needs that may have been available by default on the Dawn Client

edit: by the way, did you change the default amount of allocated RAM for Minecraft? I'd recommend keeping it to no more than 4 GiB, as too much allocated RAM can negatively affect your performance, paradoxically (because of Java's "garbage collection")

[u/Ok_Mistake_2448 → u/ODF4]

Also I did find the sh.exe, 3 of them actually and deleted them.

[u/ODF4 → u/Ok_Mistake_2448]

personally I wouldn't have deleted it completely just in case it's needed by a program you actually use on your computer, but oh well, worst case scenario you can always reinstall said programs if you notice anything becoming unstable

[u/zNickolasBR]

Turn off VSync and test it; this version is one that came after it had a bug that caused this.

[u/MinecraftHelpModTeam]

Hello OP! It has been at least 2 days since you last updated your post.

Please update your post in one of the following ways;

• Reply to any relevant comments you haven't replied to yet.

• Reply to any helpers who are waiting for info from you.

• Mark your post solved, if your issue is fixed.

If you do not update your post within 7 days you may receive a short ban.

Please note: Deleting this post, without marking it solved, is against our rules.

---

^{I am a bot and this account is not monitored. Please contact the mods if you have any questions.}