How're you getting 5?
Things like CPU speed really affect it if you are using -H 1, might be a part of it.
Perhaps higher -L values work for you (autotune it!), for me it didn't.
I've read about 150 pages looking for up-to-date info on scrypt-jane settings but still couldn't get a working one after hours of trial and error...
You wouldn't happen to have something for the 750ti and the 780ti?
For the frequency at which all this esoteric and ephemeral knowledge is being tested, published and forgotten after an update, you'd think there would be a collective bounty on a well-maintained repertoire of optimized settings for all common gpus... I wouldn't mind pitching in.
Every card is a little bit different, autotune will probably give good results.
There has been a wall of settings, on some google doc, it outdates too quickly however.