running ftb on a laptop, i can definitely say there are a few things that will help:
1) ram. dedicate more to mc if you got it. 4 gigs is a good amount
2) cpu. mc is very, very, VERY cpu dependent. the faster your cpu can twiddle those bits, the more stuff java and mc can do. graphics cards wont help, i run an integrated intel graphics chipset and ive had times where ill get 60fps, and others where im looking at a powerpoint presentation...i've run dual nvidia card setups. no difference.
3) i know its the obvious, but smooth lighting off, particles minimum, render distance short/tiny defintely help. vsync on, and if your cpu can take the abuse, run at max fps setting. if the fans get obnoxious, try balanced. default texture pack as well. those fancy texture packs do affect performance, especially beyond 16x res.
4) do you have to have mobs? peaceful mode helps in cutting out all that AI processing. sometimes it doesnt help much tho, bats love crowding dark areas, very annoying
if its not an option, light up/half slab as much land around you to keep the agressive mob spawning in check. if thats not an option, build a cursed earth grinder....force the issue and keep them spawning in one place, and out of your rendering cycles
5) something i do a lot...if you run a lot of machinery with pipes and such where entities will be flying around in view...wall them up in a way that your not looking at the entire rats nest all at the same time. splitting up the view helps a lot
6) try to keep chunk updates down. do you really need to grind 100 mobs per second? or trees? or grow 1000 crops? same with redstone, cobble generators, block placer/breakers, anything that will cause all sorts of chunky shenanigans
7) disable rain (right click the rain button in NEI). i really hate rain
8) armys of turtles/computers = lots of java threads executing interpreters translating code in minecraft, which is running in an interpreted environment already. even a row of melee turtles in a grinder can cause a lot of lag
9) applied energistics: it is wonderful at automation, but it is also a resource hog if you have walls of machines being driven by hundreds of import/export interfaces. try to optimize the processes so they dont require AE interaction. for example, you dont need to tell ae how to preprocess ores, set up your system so they are preprocessed before they even enter the AE system. have sawmills preprocess wood to planks, etc. some clever usage of ae level emitters or logistics pipes can help a lot here, you dont need a dsu storing dsu's full of cobblestone, unless you *really* want a neptune's orbit worth of cobble
6) disable mods. less mods = less ram hog, less mountains of code to run per tick. minimaps add more processing. all those little extras that you never use, turn em off. theres a lot of mods in monster, and chances are most times, you use maybe 30 out of the 100+ running in the background. dye trees is a bad one, its a frickin mob spawner without the machinery. depends on your play style, i stick mostly to the tech mods, so i disable a lot of the fantasy/mob/nature type mods.