How does one get this miner to work with multiple GPU's ?.

I have two 7970 cards, --mining-threads=1 or 2 or 3 or 4 gives the same results. Only one card is showing GPU Core activity in GPU-Z.

in the %appdata%\boold\miner_conf.json, the    "device_index": 1, or   "device_index": 0, lets me use either cards but I did not find the syntax that would allow both to work.

Also my log files always contain these two errors,  Do I have any errors in my config file ?
14-Aug-05 20:41:52.995227 [miner 1][OCL 0/1] error:  CL_INVALID_VALUE
14-Aug-05 20:41:52.995227 [miner 1][OCL 0/1] platform index must me between 0
d 4294967295

I get this errors all the time with a miner_conf.json file or without.

Running on Windows 8.1 with AMD 13.2 drivers