Issues deleting Single Player Worlds and increased lag until unplayable?

[KuraiValo]

Title:

Issues deleting Single Player Worlds and increased lag until unplayable?​

Launcher Version:

1.4.7​

Modpack:

Infinity​

Modpack Version:

1.5.1​

Log Link:

​

Details of the issue:

Hey guys, I have been having issues running Infinity recently with no idea what the issues could be. I was able to run it relatively smoothly in the earlier versions. Now when I start playing I can play just fine for 15-20 minutes before it increases the amount of RAM its using up to 95%+ (when it normally increments between 50%-70ish%), not only that but my CPU usage increases significantly and it becomes unplayable.

Also, I sometimes play on a server and do not run into these issues, but I know that works differently.

I have also ran into issues deleting my singleplayer worlds (I am pretty picky about my start and like to have different worlds for different things). I can manually delete them from the folder, but when trying to delete them from the menu it won't work. This is what I get:

Couldn't delete file ......\Feed the Beast\FTBInfinity\minecraft\saves\New World\DIM_MYST-2147483648\RedstoneEther\fmap.dat
[17:08:27] [Client thread/WARN]: Couldn't delete directory ......\Feed the Beast\FTBInfinity\minecraft\saves\New World\DIM_MYST-2147483648\RedstoneEther
[17:08:27] [Client thread/WARN]: Couldn't delete directory ......\Feed the Beast\FTBInfinity\minecraft\saves\New World\DIM_MYST-2147483648

Information:
I am running the latest version of Java (8 update 45) 64 bit
I have allocated 2.25gb of RAM out of 8.
I am running it on laptop with an Intel i7 core.
Not sure what else you may need to know....

Thanks guys!​