In regards to the wattage: Very high.
Being locked at 1.2v (thanks MSI
), Killer-watt indicated the entire rig in that screenshot was pulling 1365w from the wall (on a 1500w PSU). Minus the ~140w idle from the system, that's good for ~1300 for the 4 cards =
325-330w per card. Certainly not optimal, and missing the 3:1 khs/watt mark i strive for. It's big khs, but also big power. They are basically mini-290s.
Will do more testing later, but being volt-locked maintaining 3:1 khs/watt will be tough. I would be very, very careful attempting vbe7 bios modding with these R9 cards. I know they are basically 7xxx architecture, but there's too many brick reports to just plow ahead and mod/flash.
Ouch. Our 280x rigs are undervolted, and pull 1250W at the wall for 5 cards! We're sitting at under 230W/GPU, but we're only getting ~725KHs/GPU.
And yes, all of those R9 280x were undervolted with VBE7.
EDIT: A 100KH/s gain at the expense of adding 100W is still more profitable, but only slightly. You're talking about about $30 of increased revenue over the course of a month, with only about $10-20 of that being profit (after electric costs). Add the costs of buying larger PSUs, and the fact that you won't be able to undervolt much at those high clock speeds, and the increased temps (80C vs 60C), and you might want to reconsider.