If I have 3 ATI 6900 cards at $0.11 KW/h is it worth mining with them?

[Delicieuxz]

Hi, just wondering if it's still worth mining with a setup that has 3 6900 Radeon cards in Crossfire at an electricity cost of $0.11 kw/h

[crazyates]

http://www.bitcoinx.com/profit/

You can enter all kinds of variables to determine your profitability. Hashrate, power costs, power usage, hardware costs, etc.

[Delicieuxz]

So, if I filled everything out correctly, it currently would be losing money at around -$1.35 per day?

[mrb]

You made a mistake. What 6900 series? 6950, 6970, 6990?

For example at $0.11/kWh, with a stock 6990 (1.9 Mhash/Joule), it costs $8.20 to mine 1 BTC worth $13.50. So it is profitable. Not much, but profitable.

[Delicieuxz]

Oh, I have 3 6990 cards.

[klondike_bar]

Oh, I have 3 6990 cards.

then you should be mildly profitable, but not an a very fast speed. Any futher steps you can take for reducing your electricity cost or the power use from the mobo/HDD/CPU/etc would make the profit marin better

[crazyates]

So, if I filled everything out correctly, it currently would be losing money at around -$1.35 per day?

What did you fill out? What's your hashrate, and what does your 3x 6990 rig pull at the wall?

[Littleshop]

You made a mistake. What 6900 series? 6950, 6970, 6990?

For example at $0.11/kWh, with a stock 6990 (1.9 Mhash/Joule), it costs $8.20 to mine 1 BTC worth $13.50. So it is profitable. Not much, but profitable.

With the depreciation in the cards it is not profitable.  Unless you want to own three 6990 then it would be better to sell them now while they are worth more money.   If one of the cards dies while mining all profit is lost and you are at a loss. 

Many 7xxx series cards would be profitable to mine with if you already owned them and you were not facing new depreciation.  The 6990 stands out as a power hog, so things are not in its favor.  A 5970 is also more efficient tuned properly. 

[Delicieuxz]

Oh, I have 3 6990 cards.

then you should be mildly profitable, but not an a very fast speed. Any futher steps you can take for reducing your electricity cost or the power use from the mobo/HDD/CPU/etc would make the profit marin better

What are a few basic moves that can be taken? It's just a barebones open case rig with Mobo, CPU, ram, and gfx cards running win7, nothing else installed. I also downclocked the gpu mem speed.

[crazyates]

Oh, I have 3 6990 cards.

then you should be mildly profitable, but not an a very fast speed. Any futher steps you can take for reducing your electricity cost or the power use from the mobo/HDD/CPU/etc would make the profit marin better

What are a few basic moves that can be taken? It's just a barebones open case rig with Mobo, CPU, ram, and gfx cards running win7, nothing else installed. I also downclocked the gpu mem speed.

Undervolt! Lowering the core speed by a tiny bit and undervolting can result in huge power savings, while only costing you a small amount in hashrate.

[tacotime]

6990s are VERY fast LTC mining cards, they get about 900kh/s each.

[Delicieuxz]

Oh, I have 3 6990 cards.

then you should be mildly profitable, but not an a very fast speed. Any futher steps you can take for reducing your electricity cost or the power use from the mobo/HDD/CPU/etc would make the profit marin better

What are a few basic moves that can be taken? It's just a barebones open case rig with Mobo, CPU, ram, and gfx cards running win7, nothing else installed. I also downclocked the gpu mem speed.

Undervolt! Lowering the core speed by a tiny bit and undervolting can result in huge power savings, while only costing you a small amount in hashrate.

undervolt the cards? Is there a recommended amount to do it by?

[klondike_bar]

Oh, I have 3 6990 cards.

then you should be mildly profitable, but not an a very fast speed. Any futher steps you can take for reducing your electricity cost or the power use from the mobo/HDD/CPU/etc would make the profit marin better

What are a few basic moves that can be taken? It's just a barebones open case rig with Mobo, CPU, ram, and gfx cards running win7, nothing else installed. I also downclocked the gpu mem speed.

Undervolt! Lowering the core speed by a tiny bit and undervolting can result in huge power savings, while only costing you a small amount in hashrate.

undervolt the cards? Is there a recommended amount to do it by?

tiny amounts. IIRC, you should be able to drop the speeds by about 5%, and bring down voltage about 1-2%. try in small 0.5% or 1% steps, letting the system run for at least 30min between steps to ensure it operates normally before contiinuing.

[senseless]

Oh, I have 3 6990 cards.

then you should be mildly profitable, but not an a very fast speed. Any futher steps you can take for reducing your electricity cost or the power use from the mobo/HDD/CPU/etc would make the profit marin better

What are a few basic moves that can be taken? It's just a barebones open case rig with Mobo, CPU, ram, and gfx cards running win7, nothing else installed. I also downclocked the gpu mem speed.

Undervolt! Lowering the core speed by a tiny bit and undervolting can result in huge power savings, while only costing you a small amount in hashrate.

undervolt the cards? Is there a recommended amount to do it by?

I was running my 4x 5830s at 0.99vcore w/ roughly stock core frequency and mem clock @ 300 (i noticed hash rate started slipping if i went under 300).

At 0.10$/kwh i was making like 60$/mo of which roughly 30$ would get spent on electricity. I decided it was not worth it and shut them down. Still working on my Stratix IV FPGA dev board trying to get it mining (without much success).