genoil don't start Rx480

Why i cannot to mine with genoil? the version is 1.1.7
If i write ethminer -G -list-devices
The gpu is ok, i see my rx 480 with 8Gb
But when i start the miner with

setx GPU_FORCE_64BIT_PTR 0
setx GPU_MAX_HEAP_SIZE 100
setx GPU_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_SINGLE_ALLOC_PERCENT 100

ethminer.exe --farm-recheck 200 -G --opencl-devices 0 -S eth-eu1.nanopool.org:9999 -O 0xe2Aed33146665D88dd47735cD3Bf5a664dE04055.yyyyyyy/xxxxx@gmail.com

The miner says:

No GPU device with sufficient memory was found. can't gpu mine. Remove the -G argument

Where's the error?

Thansk