kernel compiling is usually only rough the first time through... you DO need to know what hardware you have. the rest is usually just a matter of getting rid of the rest of the cruft.
the 4GB is just the name of a patch applied to the kernel - might have something to do with how the kernel was recently patched to handle really big files over 4GB, but that's a complete guess
... it doesn't really matter.
anyway... somewhere on your system there should be a something.config file which has all the configurations for your current kernel. it's either in the /usr/src/linux directory, or it's in /boot - you can copy that config file to the directory you're going to be compiling from, and you can load it using menuconfig or xconfig.
