I have to agree that there is a problem with technic with the FPS and lag spikes. I noticed it with the current recommended build, I was getting a 40 - 60 Fps drops every 10 seconds or so and I have a very high end system which made things extremely frustrating. This is an out of the box Technic, nothing added and no config changed. I used Sphanx TP but even when I switched to Vanilla TP it stayed the same. Tried everything, reduced view distance, reduced detail on all settings. I would understand if I had a Super complex sorting system or some shit but this was after 6 hours of game-play.
I decided to install the exact same mods the old fashioned way and I even copy pasted most of the configs for the Blocks IDs. You know what, it played as smooth as a babies butt, not a single lag spike, not even when I my world loaded a Millianaire Village or Castle. I quit using Technic that day (still use Tekkit with no problems) and I run my own setup of mods with all the Technic stuff and whole shitload more using the 4k block ID mod which is claimed does not work with Technic mods, I got them working with no problem, computer genius I am not.
2 mins on the Technic Bugs subforums:
http://forums.technicpack.net/index.php/topic,10763.0.html
http://forums.technicpack.net/index.php/topic,10504.0.html
http://forums.technicpack.net/index.php/topic,10353.0.html
Keep looking through and there are more and more of these 'lag' problems and it appears to be related to memory allocation and Garbage collection. The only advice people seem to get is to allocate LESS memory. and yet I can allocate 8Gigs to my non-technic pack with zero problems.
How about the Technic Fanboys remove their heads from the Technic 'Developers'(lol?) asses for once. Congratz, you made a launcher, who cares?