i've been plagued by poor intonation on my G string since I bought my sg and i finally decided to take a stab at it tonight. im still the same amount sharp as i was when i started, and im out of room. I've already tried flipping the saddle with no luck. what's the next step i can take?
Well I've had the same problem with my Epiphone SG. I think it just may be the guitar. (probably not... and I just suck)

Try lowering/raising your action on the bridge. It will help some, but you'll have to also keep in mind the other strings intonation as well.
i'm no experto, but try and go all the way up and thennn work your way down, and make sure to double check which way to go, also be sure that you're fretting the 12th really well, not too tight or anything and at just the right spot
To the core!
i suppose it may be helpful to add that im a lazy moron and immediately put 12-56 gauge strings on the guitar when it was set up with tens. I totally understand that I need to set it up asap, i just am looking for a quick fix right now.
uh... the quick fix would be setting it up... or change the strings.
also remember that no intonation is 100% perfect... but if you're an 8th of a tone off, you need to fix it.
I will call you out from shelter burn your wings and learn their letters
Does the set of strings have a wound G? Wound G strings tend to be more in tune.
Will says:
- SmarterChild - says:
I don't know if I can help it.

Member #6 of the "I play my guitar as high as Tom Morello does" club
Gibby SGs have a tune-o-matic bridge!

I have an SG and i know it's simple to sort out!

Easy peasy to fix.

On the bridge there should be screws facing on the pickup side. yes?
If your g at the 12th fret is flat, move the saddles towards the neck. For this you turn the scredriver anti-clockwise.
If your g at the 12th fret is sharp, move the saddles away from the neck. For this you turn the scredriver clockwise.

It takes al lot of turns to do anything to the intonation, its very precise so you may need to turn it at least 5 times to see any noticeable difference on your tuner.

Summary of what i said can be found here http://www.tunemybass.com/bass_setup/setting_bass_intonation.html

although it's for setting up intonation on bass the EXACT same thing applies for guitar
oh yeah man, i know that, my problem is, I've run out of room to go backwards with the saddle, and im still sharp. im gonna have to give a wound g a shot i guess.
aha ok!

A wound G string may help, also try raising / lowering the bridge with the two screws either side on the posts as a last resort.

BTW if the wound g string doesn't completely fix it, try a higher gauge set of strings