Late Game Lag in SSP

[Anikdote]

Machine:
Win7 64bit, Java 7 update 45 I think, should be the most recent. 6GB of RAM, 8ghz AMD Dual Core, NVIDIA 8800gt.

So, my worlds always start off just fine, but I have some major issues later in the game. My very late game worlds with multiple quarries/advanced AE machines and autocrafting, mob spawning etc, I can barely even move.

What seems to be consistent is the Nether, Twilight Forest and Mystcraft ages are far worse almost regardless of the amount of stuff I have in the overworld. I've used the recommended java arguments in the launcher but so far as I'm able to tell it's had no effect whatsoever. There aren't many crashes so I don't have a log to post.

I really want to keep playing some of these worlds, but since I've had this issue in both Ultimate and now in Unleashed I'm very discouraged about creating any new worlds as I assume I'll run into the exact same issues.

Anyone else have similar issues? Any suggestions on how to resolve it? Also if you need more information let me know.

Thanks![DOUBLEPOST=1383338248][/DOUBLEPOST]Sorry I forgot to describe the symptoms.

Massive FPS drop offs (from 90+ down to zero) when loading terrain it's the worst, but just moving around my base results in the same issue.

 

[UniZero]

Your fps will gradually drop as you progress into your world. You have said it gets worse later into the game and unfortunately this is what can happen. Having lots of stuff going on at the same time will cause the fps to drop. You could turn of particles and set your render distance lower and turn off fancy graphics. But all the processing your pc has to do will cause the fps to drop over time.

 

[Anikdote]

But does that necessarily mean that I constantly go from 90+ to 0. I'd be fine with a constant rate, but it plummets frequently and makes the game unplayable and that disappoints me greatly.

 

[UniZero]

Does it do it in certain areas or all the time?

 

[Anikdote]

Always in the nether, much worth in the TF. In the Overworld it's the worst when chunks are trying to load, but generally it's terrible the longer I play in any world. I only bothered to mention it here because it's the same issue I had with Ult and now with Unleashed.

In general, it's bad everywhere, but worse in dimensions other than the overworld.

 

[UniZero]

What do you have running in the nether?

 

[Anikdote]

What do you have running in the nether?

In most of the worlds nothing other than a chunk loader, a pump, one magmatic engine and a liquid tesseract.

That's not every world though, even in worlds where I don't use the nether with a chunk loader I have the same issues.