Sorry I've not replied in a while.  Been putting all your suggestions to good use, and have managed to improve GPU performance a fair bit.

However, having installed another rig, I've hit a new problem...Available power.  In that I'm now tripping the breaker out on my electricity.

I'm going to get this sorted by having another mains feed installed, but in the mean time, I'd like to change the config of my rigs to drop the power usage, while still giving best hashrate possible.  In otherwords the most efficient power to hash ratio.

Any thoughts on the best way to achieve this?  Wans't sure whether to just drop intensity, or maybe GPU or memclock settings.  Bear in mind I'm using Ubuntu, and don't fancy tackling undervolting yet.

Each rig is currently pulling 980w at the wall, I'd like to get it down to around 700 short term if possible.

Thanks in advance for any suggestions.