There are no "power settings" per se. You just power it on and it works on default speed (auto detects best frequency and power draw (voltage), as far as I can see). In General settings you can only edit pool info. But as usual you can access Advanced Settings by typing:
http://192.168.0.12/cgi-bin/minerAdvanced.cgi
instead of:
http://192.168.0.12/cgi-bin/minerStatus.cgi
However, miner totally ignores any frequency you give to it and forwards with its auto-speed default setting.
Frequency usually ranges between 423 and 438.
Also as I said previously, it has this line near the end of Kernel Log:
frequency.c:161:get_ideal_hash_rate_GH: ideal_hash_rate = 66971
Which probably indicates it's target speed. So far after few restarts, it worked between 68 and 67 TH/s, however, after 24h or so, it would drop to around 66 TH/s which is still higher than rated 64 TH/s that is also indicated near the end of Kernel Log via this line:
frequency.c:180:get_sale_hash_rate_GH: sale_hash_rate = 64000