Allow me to summarize a reply.
As for the modpack, these days I mainly use the direwolf20 pack from FTB launcher. I think it's only just over 100 mods.
I also used to play the TolkenCraft pack (no idea how many mods it used)
As for my world age, it was generated this year so ~6 months old. I couldn't tell you play time, but I'm not really near the god-tier you describe. I do have a small-to-medium AE setup if that counts :P
Also upon generating a new world I see similar results, although in that case the client is being pretty busy generating the new world, so I'm not sure if that counts.
But how long should initial world gen take? Shouldn't the lag be mostly gone in 10-15 minutes?
Yes it certainly has less lag after those 10 minutes, but it is still pretty bad as previously described.
Back in the 1.2.5 days and Tekkit, I recall seeing insane FPS rates in the f3 debug screen. Like on the scale of 400 (I'm pretty sure that was on my gtx275 but I don't remember)
Granted plenty of other problems back then, but still...
Now for the bits that stand out above the rest from your post:
...you have no clue how java garbage collection works, do you. Please go educate yourself [vazkii.us] and then fix your settings. Better yet, just re-create the default profile, because it's already optimized for most use cases. The default "profile" that Minecraft runs under gives you 1gb of RAM, which is about perfect.
First, thank you for the link.
Second, NO, of course I don't have any Java clues, I'm no Java developer. Why would you even assume I would?
I only use Java because another program I desire to run needs it.
I can't really be expected to customize my Java settings when no one has said that is needed.
So I naturally left everything default.
And yes, it is 64 bit Java JRE
My only conclusions are that you're either you're doing it (somehow) very, very wrong...or you're intentionally spreading FUD.
Yea thanks for suggesting I'm spreading FUD.
Let me guess: "Can not reproduce, didn't try or listen to explanation. Closing ticket as NOFIX"
Seriously.. I was/am sitting here offering to run any and whatever actual tests, benchmarks, debugging, and anything else I could do to show the results of these problems to your own levels of expectation... so clearly FUD is a worth mentioning option.
I already and once again grant I could be doing something wrong.
So what the fuck do I do to do it right?!
A fresh install of FTB, fresh download of modpack, on an updated Java with default settings...
On a 6-7 month old Win7 Pro install.
I did run IE once to download Steam and a package from microsoft. All minecraft related files came from my main PC (although all came directly from Oracle, Mojang, and FTB)
In-client downloads, windows updates, and a MS security essentials DL from microsoft, are the only other internet usage that PC sees. No other web browsing is done from there.
(As nice as MSSE is on system resources, I can't say I trust it completely)
But despite all that, and not that I'm trying to force you to help me, but if there is nothing that will convince you of what I'm saying (as seems to be the case) then you have no justification for calling me a liar.