Look at the picture:

Forgive my ignorance, but the algo nist5 is not resistant to ASIC?
I think 5GH/s is enough for GPU's ... even if they were R9 280x with 7 mh/s would need more than 700 GPU's to total 5GH/s
I'm probably wrong but it seems to be a miner ASIC u.u
Rented rigs, also depends on miner version and drivers, im getting 12mhash from each 7970, so a 280x can push 13.5 at least, so with that hash, it will be half gpus