Is it possible to mine this coin with a 280x ?
Yes it is, 280x ~ 11-12 MH/s (maybe more, depends of your settings)
sgminer-x64-5.3.8-tribus
Thank you! Can you post your settings here?
Thank again

setx GPU_FORCE_64BIT_PTR 0
setx GPU_MAX_HEAP_SIZE 100
setx GPU_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
sgminer.exe --algorithm tribus --failover-only -o stratum+tcp://pool.hashbag.cc:8688 -u <WALLET_ADDRESS> -p c=DNR -o stratum+tcp://yiimp.ccminer.org:8533 -u <WALLET_ADDRESS> -p c=DNR --temp-overheat 80 --temp-cutoff 90 -I 19
if you have integrated graphics add: --gpu-platform 1
You can try -I 20 insted of -I 19
I use 1000 MHz for gpu and mem, 1012 mV (Asus 280x TOP) but you can try different combinations to squeeze more power