Minecraft 1.7.10 forge lag spike, freeze, and then crash?

[theminecraftaddict555]

Whenever i died in my adventure map that I downloaded it just starts lag spiking and then freezes and then crashes

 

Here is the log: http://pastebin.com/jkjsm8dQ

 

I am using forge and liteloader launcher at the same time

 

Mods used:

-Voxelmap 1.7.10 (Liteloader mod)

-Optifine 1.7.10 HD B4

-Custom NPCS mod 1.7.10 (forge mod)

 

[LexManos]

 

java.lang.OutOfMemoryError: Java heap space

        Memory: 82952112 bytes (79 MB) / 942145536 bytes (898 MB) up to 954728448 bytes (910 MB)

[theminecraftaddict555]

Should I add more ram to the Java console or the minecraft console?

[LexManos]

To Minecraft, obviously...

[theminecraftaddict555]

Will having 2 gigs hurt my minecraft or it will be alright? 

 

(Not sure if you need to know my specs but just in case)

I have a 4gb 1600 mhz ram and Pentium g3220 and r7 250x card