So you're pulling 600 h/s on your i7? What needs to be changed in the config or CPU file . . . I'm only pulling in 250, I didn't mess around with any of the low power settings, it's still on the stock "false" -
It's the low power setting. Instead of false, try out a multiplier. Changing mine to 5 pumped me from 140 to 359...
EDIT: Also, and this may be a linux or Iris specific thing, but (at least on the i5) doing the suggested change to sudo vi /etc/security/limits.conf dropped my start from 359 to 320, and eventually my hashrate dropped to 180. Commenting it out brought everything back to 359 and stable, so I suggest testing it if you want, but it doesn't seem necessary (if you are still getting locked RAM messages, I was able to get rid of them by sudo running the miner, but I don't think they had an effect on hashrate)
Also, just fyi, setting the low power setting to 5 upped my consumption a wopping 3W. So 140-200h/s was around 40W, and 359 is around 43W. While the ROI on the i5 model is much, much slower, for low power/low heat setups, the return is pretty great.