I'm using 5, 0, 30. Not sure if it's helping me or not. It sure isn't hindering anything.
You want to find a nice even balance between your hash rate and your WU to get as close to 1:1 as you can with them with as low rejects as possible. Once you have that and things are stable, you should have your best settings. I found these two pages very helpful for my current xintensity and thread settings. And yeah, any hardware errors at all is bad.

Posts 1189 and 1194 specifically -
https://litecointalk.org/index.php?topic=6842.1185Post 129 -
https://litecointalk.org/index.php?topic=13190.msg112035#msg112035I'm trying to adapt this to my 290X's (Sapphire as well). I had to bump my threads back to 27400 because I was getting scores of hardware errors. May I ask what scantime/queue/expiry settings you would advise?
So far things look hopeful, though I'm not sure why my old settings would be any worse than this. Thanks for taking the time to share this!