Best way to stop lag in minecraft?

I recently downloaded a new minecraft mod called the Yogscast complete pack but it is lagging out like crazy. I tried searching for viruses and found that I had none. I also tried cleaning the registry, defragmenting my hard disk, and deleting all temporary files but nothing is working. I also changed the video settings in the game to the best/fastest ones but the game still just lags to the point where I can't play because I can barely move. I'm stumped because my other mods (tekkit, voltz, etc) work fine but this one is horrible. I've been waiting months to play this mod and i'm totally lost with what to do.

Go into your settings and reduce the amount of chunks that load.

Well the Yogscast Complete Pack is a combination of over 50 mods, if you don't have a good computer I'm afraid it will lag. Your best bet is to set view on tiny and to change to Fast.

There's nothing you can do really. Your computer probably isn't very powerful.