tekkit Can not run Tekkit at all

[SteamingBullet]

About a year ago I used to play Tekkit a lot with my friends on a server and everything. Recently we had the urge the play it again, and as such we all updated and I downloaded a new server. I set up the server, and they joined.... But I couldn't. I tried creating single player maps and it didn't work. It'd get stuck at building terrain, and occasionally shutting down internal server, and it would then crash to the Technic Launcher or I'd have to go to task manager and stop it.

I have done the following: Restart computer, restart Tekkit/Technic, Uninstall Tekkit/Minecraft/Java/Technic and reinstall all, updated everything on my computer (Java, Windows Update, etc.), and I even tried giving Tekkit more ram/memory.

Eventually I questioned minecraft in general, and it worked without any problems. After that I tried another modpack, Hexxit... Worked flawlessly.

I am using Windows 8.1, 64 bit, 8 GB of RAM, and I can not understand how to fix this.

Attached to this is one of the many crash reports I've received.

crash-2015-04-01_14.04.17-client.txt

[Munaus]

post your log on a pastebin site, I'm not downloading anything from you

use pastebin.com or paste.ubuntu.com

[SteamingBullet]

post your log on a pastebin site, I'm not downloading anything from you

use pastebin.com or paste.ubuntu.com

​http://pastebin.com/BJ6tDRJQ

Here you go

[Munaus]

Caused by: java.lang.OutOfMemoryError: GC overhead limit exceeded

memory issue. I don't remember how to fix this, someone knowledgeable might know

[SteamingBullet]

Thanks for sorta narrowing it down. Raising or decreasing RAM given to java doesn't help, but upon looking I seem to get both a client and server error whenever it crashes. The first one I sent being the server, and the client being

http://pastebin.com/nQwYu3fE

Both with different causes. Not sure why this is happening, but any further info would help.

[Torezu]

Seems to me the LegacyJavaFixer might be required, since you're running a 1.6.4 pack on Java 8.  Try finding that and dropping it in your mods folder.

[SteamingBullet]

If I am correct, the LegacyJavaFixer is included in the current version of Tekkit. I even looked myself and found it there. It goes to the main menu fine, options and all the menus, just going into the actual game is the problem.