Although the poster expresses a preference for raw power, anyone else considering a new bitcoin mining rig should optimise three separate features...
1. maximum MH/sec per GPU card - fewer GPU cards mean fewer motherboards, CPUs, and power supplies, software configuration, and monitoring effort.
2. minimum purchase expense per card - with mining difficulty exponentially increasing due to exponential growth of total network hashrate, its possible that certain expensive mining rigs will not payback their purchase price after subtracting gains from selling off the used components later.
3. minimum power consumption per card - this ongoing cost determines the point at which bitcoin mining ultimately becomes unprofitable on a cash flow basis. Lower power consumption per card makes it easier to cool the card and also to overclock it.
The Radeon HD 6990 is optimal only for criteria #1 above. The owner of the famous 48 GH/sec mining rig featured on YouTube says that he is "upgrading" his vast number of 6990 cards with 5830s as he can obtain them. Why? Because of criteria #3 above.
I chose to construct my 1200 MH/sec rig using three case-less motherboards with two overclocked HD 5770 GPU cards each. The HD 5770 cards were the most optimal for me using these criteria considering the limited choices at Newegg in the USA at the time of purchase. The power drawn by the shared UPS is 850 watts.
1. maximum MH/sec per GPU card - fewer GPU cards mean fewer motherboards, CPUs, and power supplies, software configuration, and monitoring effort.
2. minimum purchase expense per card - with mining difficulty exponentially increasing due to exponential growth of total network hashrate, its possible that certain expensive mining rigs will not payback their purchase price after subtracting gains from selling off the used components later.
3. minimum power consumption per card - this ongoing cost determines the point at which bitcoin mining ultimately becomes unprofitable on a cash flow basis. Lower power consumption per card makes it easier to cool the card and also to overclock it.
The Radeon HD 6990 is optimal only for criteria #1 above. The owner of the famous 48 GH/sec mining rig featured on YouTube says that he is "upgrading" his vast number of 6990 cards with 5830s as he can obtain them. Why? Because of criteria #3 above.
I chose to construct my 1200 MH/sec rig using three case-less motherboards with two overclocked HD 5770 GPU cards each. The HD 5770 cards were the most optimal for me using these criteria considering the limited choices at Newegg in the USA at the time of purchase. The power drawn by the shared UPS is 850 watts.
x2.... I'm running a case less mobo now with 2 5830s. Soon to be 3 as soon as my cables show up. Should also help out with the heat issue.
