Bitcoin Forum

I have access to run maybe a couple of hundred or more machines with which i can put CPU miners, they don't have gpu's of significance in. These machines are usually powered up and running nothing 60% of the day. Would it be sensible to set these up to mine as a whole cluster on slush or deep bit or be a waste of time? Some machines could run a gpu miner as well. I estimate the average Mh/s could be around 2-5

Not worth it.

Sounds like a terrible waste of time and a good way to get fired and bring some bad press to bitcoin in the process.

Wel fired is not possible. I own these machines. Secondly, I'm already paying costs for people leaving them on.

If you don't care about extra power usage and costs, go for it.

Mining will increase power usage.  As an example, my iMac burns 35 more watts to CPU mine versus be idle.  Since CPU mining yields so little, the power may not be worth it.  The odds of a CPU generating a single block have lately become so astronomical that most CPUs will generate nothing even running for months or years.

You should run the numbers...get one of those Kill-A-Watt devices...measure the normal power draw and the draw when mining.  Then calculate your overall hash rate and the amount of coins you would generate.  Using the exchange rate and the price of the additional electricity usage, you should be able to calculate whether it will cost you more in electricity than the value of the bitcoins you'll generate.  If your objective is to acquire bitcoins and the electricity costs more than the value of what you generate, then just buy the bitcoins.  OTOH, if you come out ahead, then generate them and re-evaluate that equation as the exchange rate and difficulty fluctuate.

If you own them it's an even worse idea. If they belonged to someone else at least you wouldn't be paying for power and cooling. The difference between idle/sleep (left on) and load power consumption (hashing) is going to be significant. You could probably buy a GPU capable of a higher total hashrate for less than the power cost of using a hundred PCs to hash for a day or two.

Sure, but, with respect to your electricity bill, being on and not doing anything is different than being on and working at 100%.  Say you use 100 machines.  If each of those machines did 5Mhash/s then you'd get 500Mhash/s from the whole lot.  Let's say that each machine only draws 100W at full load.  That's 10,000W for 500Mhash/s.  Now compare that to my single 6990 GPU system which draws 500W and does 780Mhash/s.  Those 100 systems would use 20x more energy than my 1 system but would produce fewer bitcoins.

Go back to sending spam with your botnets. You'll make more money.