Game freezes at "building terrain" and if you get in it is very laggy

[efgh58]

Hello our there!!!
I have put together a modpack in the technic laucncher, tested it with te native vanilla in technic launcher, and even got it to download into my PC. So ithought  it was all working, opened it from technic launcher. It loads very long at the mojang logo, but I think thats OK because I have got nearly 90 mods installed. Then I wanted to create a world which has worked perfectly when testing on native vanilla. Now it stucks on the dirt background with "building terrain" or something. When I waited, it did work after some time (only once), but then the game itself was laggy, taking ages to open any (chest) inventory and building new chunks.

Now my question is: How do I get to fix it (It´s a modpack for me and my friends making a server on nitrado)?
Is there another solution than deleting some mods, because for the modpack it would be very nice if all mods could stay and I would realy fu ing hate it to redesign it over and over to find the perfect lag rate)
(It is not because from my computer, because on native vanillia it has worked perfectly)

Mod´s list:

 

My Specs:
Acer Aspire 7750G
Intel core i5 2,3 Ghz
4 Gig RAM
64bit

If you could write me back, there are some more infos:
I´m probably going to delete artifice, and morebiomesxl (or sth like that)
If I´m havingf any other expensive mods, please write me some of the most RAM-taking ones....