Shieetttt, we survival blox and me without an in depth explanation on how to set up so people can hop in.
Okay what you'll need first is the brand spanking new launcher called ATLauncher which you can grab here:http://www.atlauncher.com/downloads/
Download for your preferred OS and put it in it's own little folder
Click it and it'll generate files in the folder
If it hasn't loaded up the main menu page after everything is generated, go ahead and click the launcher again so the Main Menu pops up. Once the Main Menu of the Launcher loads up you'll want to go ahead and set up your account on it, so on the right side you'll see a couple gray tabs, go ahead and hit the "Accounts" tab and Add An Account. Put in your Minecraft User Name and Password as usual.
Once that's set hit the "Packs" tab and the very first one should be "Yogcast Complete Pack", since that's the one we're running. In that section go ahead and click "New Instance". A new menu will pop up and you'll want to set the "Version to Install" drop down menu to "126.96.36.199-RR-YOGS (Minecraft 1.6.4)", then hit the "Install" button.
It'll probably ask you to put in you username and password again, so go ahead and do that again. Afterwards a new menu should pop up.
Okay, this is were things get really weird for a bit, so don't fret. What this menu shows are all the mods that come in the modpack, on the left you have the mandatory mods that it'll download that should all be greyed out, so you can't change nothing. Now, on the Right Side you should see a bunch of unchecked boxes. NOW THIS IS IMPORTANT. You'll want to check ALL THE BOXES on the right side EXCEPT FOR 3.
First one should be EiralIRC which is an IRC mod that will constantly bombard your chatbox with the whines and twines of Minecraft kiddies hanging out on an IRC chatroom, and I'm pretty sure no one what's that, so leave that unchecked.
Next is Mapwritter, which is a mod that will automatically draw and save the sever map to your computer as you walk about the world in some weird graphic format, but that's pretty much useless as you'll get an in-game map anyway, so leave that unchecked.
LASTLY, there are two MAP MODS you can choose from, PICK ONE!!
They are Rei's Minimap and Voxel Map (aka Zan's Minimap)
Pick ONE of them or else you'll get HOT GLITCHY MINIMAP ON MINIMAP ACTION.
So in summary, everything on the left is checked and everything on the right is checked EXCEPT FOR 3 THINGS PREVIOUSLY DESCRIBED!
After you're done, just hit "Install"
Now here comes the performance bit
Go to the "Settings" tab and click it, now a few new tabs at the top of the menu should appear, go ahead and click the "Java/Minecraft" tab.
In the "Memory/RAM" section, depending on how much RAM you have on your machine will depend on what value this will be:
-If you're running 4GB of RAM or less, minimum SUGGESTED requirement is to set the drop down menu to "2048MB"
-If you're running 8GB of RAM or more, minimum SUGGESTED requirement is "4096MB"
Of course your mileage may vary, if you're running 4GB of RAM and want to set it to "4096MB" OR LESS, then by all means go for it. Mess around with the values, see what works for you!~
Now this is important:
In the PermGen Size box, set it to 256 OR ELSE YOUR CLIENT WILL ALWAYS CRASH, SO DO THIS!
Once you're done with these settings, hit "Save" and go to the "Instances" tab. You'll see the modpack you downloaded, so go ahead and click "Play" to load up the client