Also, do you remember the old "Optifine" mod that boosted frame-rate performance of Minecraft and added a few extra display options? The Tekkit Classic launcher included it by default, but FTB does
not. The developer of Optifine has actually asked that modpack distributors not include his work. No worries! You can still get Optifine, and you can get it to work with the FTB launcher pretty easily.
Download the latest version of Optifine from this thread:
http://www.minecraftforum.net/topic/...and-much-more/
Quit Minecraft if it's running, and restart the FTB launcher. When the modpack screen is visible, select Direwolf20 (as usual), and click the "Edit Mod Pack" button. Click the JarMods tab, and click the "Add Mod" button on the bottom right. Select the zip file you downloaded, and it should appear in the "Enabled Mods" list like this:
Adding a mod this way copies the zip file into the mod's own directory. So, you can trash the zip you downloaded.