Just posted a optimized x13mod bin file for 7950 (and possibly 280x,290x and other 6xxx,7xxx)
compiled with sgminer 4.1.0 cat 14.6RC2 for those not wanting to upgrade to 14.6 RC2 at
https://bitcointalk.org/index.php?topic=666252.0
Please post in my thread if this works for you