pw, are you sure about the 4x factor calculation(x11 vs scrypt)? my rigs report a 2.85x-3.13x x11 vs scrypt. is it a problem on my end or a typo?
If you are using something like AMD 7950/7970 R9 270/280/290 you should be getting ~4x. Upgrade sgminer to x11mod if you haven't yet.