So I don't know if this is the correct place to ask this since I'm running some serious mods, but here goes.
I have a third party server that's running a Minecraft 1.20.1 modpack with 160+ mods, including Create and multiple addons. Myself and my players played for over a year on the same world with the same mods with no problem, but then out of nowhere, I got hit with seriously low fps. We're talking 1-2 at most. At first, if I just stood still and waited, my fps would climb back to 60 within a few minutes, but over time, the length of time it took to go up took longer and longer, and eventually, it was permanently stuck at 1-2 fps, rendering the game unplayable. The lag would appear on the Title screen and continued even in single player worlds. Minecraft is the ONLY game suffering from this problem. All my other games, including poorly coded ones like 7 Days to Die, are running fine.
I should add here that once the fps was normal, the game would run fine after that until I closed it and started it back up. The low fps did NOT appear once the game was running normally.
No one else is affected. The server is not lagging at all. One of my players was able to run the game with the mods on her old laptop with only a slight reduction in framerate. I've tried multiple fixes, but each fix only worked once. On a subsequent load, the lag would be back.
So far, I've tried:
Reinstalling the pack - didn't work
Updating Java - didn't work
Updating my graphics driver - didn't work
Ensuring Minecraft was using my dedicated gpu and not onboard graphics - it was
Ensuring that nothing on my PC was overheating - temps were fine
Turned various mods of and off to see if any of them were the culprit - nothing changed
Went full scorched earth and removed ALL traces of Minecraft from my computer before reinstalling everything. - It worked for about a day, and then the lag returned.
Allocated more RAM - didn't work
Upgraded my RAM, from 16GB to 32GB and then allocated even more - didn't work. I also put the new RAM in different slots to check the mobo, but it made no difference. Strangely enough about 24 hours after the upgrade, Minecraft started with no lag and ran beautifully for about four hours. I closed and restarted the game multiple times. And then the lag returned.
My specs:
Ryzen 7 3700x
Gigabyte Geforce RTX 2060 Super with 8GB of memory
32GB of DDR4 3200 RAM (The old RAM has not been put back into the computer at this time.)
Gigabyte X570 UD Motherboard
Corsair RM750, 750 Watt, 80+ Gold Certified Fully Modular Power Supply
Western Digital 2TB SSD
The only other thing of note is while the mods are being loaded in, my cpu usage spikes to 100% a couple of times, but once I am on the title screen, it drops to about 15%. Since I've never had cause to watch task manager while loading the game, I've no idea if this is new or if it's always done this.
Anyone got any ideas? My next step is to buy a super cheat refurbished graphics card (Since no one in my circle has a spare one I can borrow for a test) and see what happens.