You need to read up on how Xmn works, and why people over in the Support sections are exasperated at Mojang for even adding it; increasing it is the number one cause of lag spikes not due to hardware/software since what it does is cause the garbage collector to not run until however much garbage has piled up; more garbage = more work for the GC = bigger lag spikes:
Java is horrible at handling large amounts of RAM. And what's worse you assigned most of the Heap as Young Generation. The Garbage Collector must be regularly having seizures, having to clean 25GB of waste memory. This is not "more RAM". This is a recipe for lag hell.
If you don't know what Xmn is, DON'T touch it. Or better yet, remove the argument completely.
And drop max heap to something manageable like 4GB.
Plus, for me the game runs perfectly fine with only 768 MB allocated and doesn't even use that much, even on modded Minecraft without Xmn and on 32 bit Java (OS, 3 GB physical RAM); I only use -Xmx768M -Xms768m -Xss1024K. BTW, Xms is how you'd properly set an initial minimum memory allocation, not that it even matters because the JVM will allocate as much as the game needs and the game is incapable of using any additional memory - anything beyond is purely garbage, which is why in this post the game only used a few percent of the memory with 4 GB allocated and about the same as with 512 MB - ironically, FPS seemed to decrease as RAM increased (144 FPS at 512 MB (49% used), 137 FPS at 1 GB (33% used), 130 FPS at 2 GB (11% used), and 123 FPS at 4 GB (8% used) - I've seen people allocating so much RAM that only 1-2% was being used - and was completely unusable by any other programs since Java ties it all up!).
Everyone knows the preset is Xmx1GB Xmn 128M
It doesnt take all 1GB.
Many people know how to allocate more RAM now by insalling Java 64bit and change Xmx{}GB now.
But it still doesnt take all the RAM as u allocated.
In fact i tried to set Xmx214GB Xmn 512M
It only gave me Maximum 6.3GB as I recorded.
Now I want Maximum 3.5GB
And I set Xmx7000M Xmn 3500M
It work prety well.
Interesting...
MY MODPACK! ~300 MODS! 1.10.2-1.12.2, 1.15.2!
You need to read up on how Xmn works, and why people over in the Support sections are exasperated at Mojang for even adding it; increasing it is the number one cause of lag spikes not due to hardware/software since what it does is cause the garbage collector to not run until however much garbage has piled up; more garbage = more work for the GC = bigger lag spikes:
Plus, for me the game runs perfectly fine with only 768 MB allocated and doesn't even use that much, even on modded Minecraft without Xmn and on 32 bit Java (OS, 3 GB physical RAM); I only use -Xmx768M -Xms768m -Xss1024K. BTW, Xms is how you'd properly set an initial minimum memory allocation, not that it even matters because the JVM will allocate as much as the game needs and the game is incapable of using any additional memory - anything beyond is purely garbage, which is why in this post the game only used a few percent of the memory with 4 GB allocated and about the same as with 512 MB - ironically, FPS seemed to decrease as RAM increased (144 FPS at 512 MB (49% used), 137 FPS at 1 GB (33% used), 130 FPS at 2 GB (11% used), and 123 FPS at 4 GB (8% used) - I've seen people allocating so much RAM that only 1-2% was being used - and was completely unusable by any other programs since Java ties it all up!).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?