I had issues with running 5 x 290 - not enough memory under windows (8GB) so I am running agian BAMT 1.3 (low rejects) and I will add more memory tommorow morning.
PS, this should help you with your RAM issues:
-I 20 -g 1 --lookup-gap 2 -w 256 --thread-concurrency 32765 --gpu-engine 1005 --gpu-memclock 1500 --gpu-powertune 50
If you still have trouble, drop -I to 19.