Dude I missed what you typed on speed before.

I'm getting 4.7 Mh/s per card on my 290 rigs, heavily under-volted with very conservative settings.  I live next to my rigs so they must remain cool and quiet.


http://i1242.photobucket.com/albums/gg530/Ignition75/290_zps86dc00c5.jpg


Following settings: -g 2 -w 256 --thread-concurrency 8192 -I 17 --expiry 1 --queue 0 --scan-time 1 --no-submit-stale

GPU Clock 940  Memory Clock 1130

SGMiner5 + 14.6 Beta drivers.

You should be getting at least 75 Mh/s with 16 x 290 cards, you can get 100 Mh/s easy if you don't worry about fan noise or temps.  Just run higher clocks and perhaps run Intensity 18 or rawintensity 100,000.

Hope this helps mate...