Bitcoin Forum

Hello,

I have recently found out about bitcoins and I would like to start mining. From what I heard, the difficulty of getting BTC is going up exponentially.

With only an HD 5850 churning out 370mh/s, is it a viable and profitable opportunity?

All tips and advice are welcome.

Maybe short-term, but within a few months, I think profitability of mining will start decreasing considerably. FPGAs are going to become much more popular fairly soon if the BFL units are consistent and don't burn out within a few months. Mid-term, I think this will push difficulty up, and cause an even weaker correlation between price and difficulty. FPGA miners probably don't have much else to do with them and they'll have no problem mining profitably down to something like $.10/BTC at current difficulty. It will decrease overall profitability as people upgrade to energy-efficient rigs since FPGA miners won't really have any incentive to stop mining until GPU miners are already pushed waaaay out.

But, if you already have a card and aren't using it -- you could probably mine in the black, assuming your electricity rate isn't >$.12/kWh given you only have one card on the system and components probably not selected for maximum efficiency mining. If you can pull your wattage # (Kill-A-Watts have been selling on Amazon for $16 with a coupon lately), you can plug your #s in @ http://bitcoinx.com/profit/index.php -- then just mine until it's no longer profitable.

As far as opportunity, don't be expecting anything beyond a few extra bucks per month with just one card after electricity.

Electricity is quite cheap in my area, at 3 cents a kilowatt, (lucky for me my powerplant runs on natural gas = cheap  :))

Electricity at the moment does not seem to be a very big concern, although they appear to be increasing the rate slightly in the future.

I may be able to get another 5850 to crossfire my unit to get an average of 700mh/s.

This is my old gaming rig so making a huge profit is not too concerning.

Thank you for your help however.

The price is starting to go back up on bitcoins and while a lot of people are jumping out of the game there are a lot of veteran miners still buying. If you already have a 5850 I would suggest going ahead and mining! You will make more than you spend in electricity (assuming you don't pay an absurd amount). I would also highly suggest downclocking the memory and undervaluing to save a lot of electricity and heat. You'd be surprised how much it can help  :). Here's and compiled undervolting results link https://bitcointalk.org/index.php?topic=65997.0 (https://bitcointalk.org/index.php?topic=65997.0). There are also other posts about underclocking out there. If you need any of those links just ask. Best of luck!

With that kind of electricity cost I would suggest overclocking that thing like crazy and setting your memory to 300 (ideal for 5850 in most cases)! You will also get better hash rates with 300 memory.

Quite interesting..

What exactly is undervaluing? Do you only bring down the memory clock speed and voltage or also the core clock?

Thank you  :)

EDIT:

What is a good OC tool to use? Asus smartdoctor seems to be quite limited.

Would underclocking the memory also let me achieve higher core rates?

With electricity that cheap, issue shares on GLBSE, ask for loans - mine like crazy. There are many GPU mining farms out there paying >$.10/kWh. You have a fantastic advantage there.

He meant to say undervolt. Underclock mem speed, then experiment to get best ratio of high core speed to low voltage. With electricity so cheap, your biggest expense I'd guess would be component failure. Running cards hot or at a higher voltage will kill them much quicker than keeping them undervolted. That said, I had 7 5850s running for about 10 months overclocked @ stock voltage without any problems, but others seem much less lucky.


If you're running the same non-reference 5850s (ASUS DirectCU cards) I'm running, it can be difficult. MSI Afterburner is well-regarded for overclocking, but it takes some effort to get it to function correctly with those cards (I couldn't get it to work). I did use ATI Tray Tools with good success on those cards, however.

Underclocking the memory speed (which is irrelevant when mining, but you generally shouldn't clock it below 300MHz or it may become unstable) will cause the card to draw less power while operating, thus allowing you to raise the core speed (what is used in mining) without needing to increase voltage.

Yeah sorry my computer autocorrected my undervolt to undervalue lol!

Do you remember what your clock speeds were with default voltage?

900MHz when new at stock voltage, after a long time of running, though, they were having trouble with 100% uptime above 895MHz core, but it differed a bit with each individual card. If increasing the voltage, the max stable core clock was something like 945MHz, IIRC. Worth noting those speeds were stable when I was doing something like web-browsing, so you might be able to go a fair bit above that if you don't do anything with the computer when you have higher clock settings -- dunno. At any rate, you won't be able to do anything graphics-intensive at those speeds, and mem speed becomes important when you're gaming. I was doing alright with core speed of 820MHz, mem speed of 800MHz @ stock voltage when mining and doing something putting extra strain on the cards, fwiw.

With MSI Afterburner my cards appear to be great at 900/300. I had to raise the voltage quite a bit though. Not sure if that's bad or not but the card is faring well at 61C.

Thanks for the help!

How much did you raise the voltage? Voltage increase to an extent won't hurt in the short run but since mining is usually 24/7 it can be bad in the long run and dramatically decrease the life of the card. I wouldn't suggest going much over stock voltage if you do 24/7. I personally don't go above stock voltage at all but its fine to increase voltage like 3% safely.