I believe the setting is quite pool specific. I used to use --queue 1 but found I got a lower DOA rate & slightly better performance using --queue 0 with the cpu at ~80% - but I'm pointing mine at p2pool so maybe that's why? Load is currently: 1.58 1.62 1.40 @ 237.5
Thanks for the feedback. I'm pointing them at Slush, with Bitminter as a backup (failover).
Don't see how the CPU% is dependent on the OC, but I ran tests on 3 different clocks, with 3 different queue settings. The load was pretty high on all of them.