While I don't know the specifics, a decent computer is highly recommended. No it won't run on your toaster. While I am not certain it is required, I will not give support for 32-bit operating systems and java. As for Java, RTY 2 requires at least Java 7, although Java 8 is highly recommended.
How much RAM do I need?
I would say minimum 1GB. Recommended 2GB.
It's slow/ It's laggy what can I do?
First of, go and install Optifine and Fastcraft and test if it's still slow, by using these two mods you can typically double you FPS. If that doesn't help, follow the guide bellow.
FPS Guide
Spoiler
1. Install Fastcraft and Optifine
To do this, you need to find your mod directory. From your install directory it should be in Install\ReleasetheYukkuri\minecraft\mods. You can find out where FTB is installed by going to the settings page and see what "Install Folder" is set to. You can also be brought directly to this folder by clicking the "Edit Mod Pack" button, and from there, click on the "Open Folder" button.
After you have found your mod directory download the .jar files and drop them into the folder. Links: https://optifine.net/home http://forum.industrial-craft.net/index.php?page=Thread&threadID=10820
2. Make sure that your minecraft settings are suitable. You don't really need a rendering distance higher than 8.
3. Give Minecraft somewhere between 2-3 GB of ram. Not less, not more (more can be just as damaging as less)
4. Start editing configs. Down below I'll show most of the relevant options. Do note that you don't have to do all of these changes, for example, you don't have to disable animations for blocks, it just helps improve performance.
You can find the config files in the config folder. The config folder should be located at Install\ReleasetheYukkuri\minecraft\config
cofh/core/client.cfg
EnableShaderEffects=false
EnableAnimatedTextures=false
EnableParticles=false
EnhancedPortals/config.cfg
DisableParticles=false
forestry/common.conf
performance.particleFX.enabled=false
AWWayofTime.cfg
UseFancyBoundArmour=false
BiblioCraft.cfg
Case=true
DinnerPlate=true
DiscRack=true
FancySign=true
Label=true
PotionShelf=true
Shelf=true
Table=true
ToolRack=true
Botania.cfg (There is a lot more options here if you want to check them out)
lexicon.render.3D=true
powerSystem.subtle=false
shaders.enabled=true
ExtraUtilities.cfg
disablePortalAnimation=true
Hats.cfg
renderHats=0
LogisticsPipes.cfg
enableParticleFX=false
ProjectRed.cfg
3Dlogicwires=false
Thaumcraft.cfg
glowing_taint=false
shaders=false
More stuff will come here as it's relevant.




