Ok so all the people who are seeming to have all of these new performance issues with 1.7, are u now playing in a single player world run on your won system and not on a multiplayer server which is doing most of the heavy lifting in regards to world gen and the like.
I believe Impact said that he played on a personal server in an earlier post while testing this pack, well ding ding ding thats part of the reason you arent experiencing the performance issues that most of us who are playing on a single player world, running on our own system.(This is one of the reasons i almost always play on servers or play on skyblock packs where there isnt much world to gen)
Not saying that 1.7 doesnt have issues, there is obviously something causing a memory leak becuase i have seen the same steady 10% then it will quickly raise into the 80%+ range. So this new memory problem compounded with the fact that most of these packs aren't 100% "stable" so big servers that would run these packs well arent up and going yet, meaning we run single player versions of these packs, is all making it harder for the "average PC" to run.
Just my 2 cents.
Fluff