Serious Lag Spikes Caused by Certain Actions

[Zuma]

So, something that has been keeping me from playing is these serious lag spikes that sometimes occur. When I load my world like two different times in one client instance I start to get these lag spikes that happen every 5 seconds. Usually it goes from 150 fps down to 50 but completely freezes the game for 1 second. I also noticed this happening when I enter the nether or leave it. Also a while ago when I was playing I noticed MystCraft teleports would cause this too.

The only way to fix this is to completely restarting the instance. This is extremely annoying.

Any help would be appreciated.
-Spencer, Zuma

PC SPECS:
Graphics: GeForce GTX 670, MSI OC Edition
Processor: Intel Core i7-2600 at 3.40GHz Hyperthreaded to 8 CPU's
Cooler: Hyper 212 Evo
Soundcard: ASUS Xonar DX 7.1
Memory: 16GB at 1333 (4x4GB)
HDD: 2TB WD Caviar Black
SSD: Samsung 840 Pro Series 128GB
Supply: CoolerMaster 750W
Case: CoolerMaster HAF 912 Mid-Tower
Motherboard/Chipset: MSI Z77-GD65

 

[Rick]

How much ram is FTB set to use? Even my system lags alot if i dont allocate enough RAM (should put 2GB or more).

 

[Zuma]

How much ram is FTB set to use? Even my system lags alot if i dont allocate enough RAM (should put 2GB or more).

Ahh, K I stuck it up to 6GB, that should be enough. eh? Lol! Gonna try it now.

 

[UniZero]

I would not allocate any more then 5gb. Try adding the jvm arguments from here to the additional parameters box in the advanced options on the launcher

 

[Zuma]

I would not allocate any more then 5gb. Try adding the jvm arguments from here to the additional parameters box in the advanced options on the launcher

Okay it stopped doing the stutters when I allocated more than 1 GB. Then just cause it couldn't hurt anything I put that giant code thingy in the settings of launcher.

 

[UniZero]

Okay it stopped doing the stutters when I allocated more than 1 GB. Then just cause it couldn't hurt anything I put that giant code thingy in the settings of launcher.

Those arguments are designed to increase performance when using a heavily modded minecraft.