No.
7970's
cannot obtain
stable settings at intensities above 13.
I don't know why, but I haven't heard of one case where anyone was able to attain a stable configuration with an -I 13+
Set -g to 2, -I to 13, and --thread-concurrency to 8192
Anyone who says intensities above 13 are stable for 7970s don't know what they are talking about.
btw, did anyone receive your 15LTC reward yet?

Incorrect.
7970s run rock solid stable at -I 20 as long as the thread-concurrency is above 16384 and gpu-threads = 1.
They're just slightly faster with -I13 / 8192 / gpu-threads:2 [680kH vs 710 or so]