Hey guys,
haven't been on here a lot lately, I know. Sorry about that, busy times...
Anyway, I found out about a little something called "bitcoin" yesterday. In short, it's an alternative sort of "internet currency" that has been around since 2009 (if only someone had mentioned it to me 1-2 years ago...). The idea is to trade the bitcoin (BTC) for real money like USD or €, or even gold. Some websites also offer products and services that you can pay by using bitcoins: https://en.bitcoin.it/wiki/Trade
While this concept isn't new, there is something about bitcoin that makes it VERY interesting to us crunchers - you can generate ("mine") bitcoins by using your computer. Similar to crunching, it uses your computer's resources to generate these "coins".
Now, I've been at this for a day now, and I don't know everything yet, but I can tell you it works. I'm also going to tell you what you need to know in a nutshell, so everyone can profit while it lasts. Ok then, let's get started with the How to.
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What you need:
1. One or more fairly recent, ATI-based GPUs. HD5xxx and up are best at this, Nvidias are a lot worse, CPU is useless
1a. The right driver. Be sure to download the current ATI driver WITH APP, else it won't work. You can also download the OpenCL SDK separately. With HD5xxx cards, performance is supposed to be best with the older 2.1 SDK (I can confirm this). For HD6xxx, use the current 2.4 SDK because 2.1 won't work with them.
2. Good GPU cooling, as with all GPU crunching/mining projects
3. Preferably cheap electricity, but it's still worth running even in more expensive regions (like Germany...), provided you have the right hardware
Performance is measured in MHash/s (Mega-Hashes per second). Here is an overview of what different cards can do: https://en.bitcoin.it/wiki/Mining_hardware_comparison
As we can see, HD5870 and HD5850 cards are among the best performers, closely followed by current HD68 and HD69 series cards.
Setting it up
Setting up is quite simple really. First, you have to make a choice between joining a so-called mining pool or going solo. I strongly recommend using a mining pool, because that will provide you with a steady payout and work better in general.
0. You need to download the bitcoin core app that acts as a "digital wallet", it contains the key where it saves the amount of bitcoins that you have earned. Download here: http://www.bitcoin.org/
Starting up, it will show your bitcoin address (a long key that is generated randomly).
1. Assuming you are joining a mining pool, just go to their website and register. I use the deepnet pool, which is currently the biggest one and also has the best (lowest) fees from what I could tell: https://deepbit.net
Edit: I now use the BCT Guild pool, which has no fees at all! Recommended (you can still donate a % to help keep it running, but you don't have to): http://btcguild.com
When creating your deepbit or BCT guild account, you have to enter your bitcoin address so the pool knows where to send your coins to. Just copy & paste the address key from the bitcoin core app you previously installed.
You will also need to set up a "worker" in your deepbit or BCT guild account, but that's kinda straight-forward really.
2. After you have created your mining pool account, download and unpack the GUI miner tool to a destination of your choosing: http://forum.bitcoin.org/?topic=3878.0
3. Start guiminer.exe, you'll find the following window:
4. Select "deepbit" or "BCT Guild" in the "Server" drop-down menu and enter the e-mail (deepbit) or name (BCT Guild) and password matching the worker's which you created on deepbit/BCT Guild
5. Under "Device", select your GPU. It will show your CPU and all available GPUs.
6. Optionally, you can add extra flags. For ATI HD5xxx and above, the "-v -w128" flags are supposed to be ideal. Don't know about other cards, check the list I posted in the beginning.
7. That's it - just hit "start mining" and you GPU will start working.
8. If you have more than 1 GPU, set up a 2nd (3rd, 4th etc) worked thread. "File" --> "New OpenCL Miner" --> choose any name you like (I used "GPU2") and set it up exactly the same way as the first one, bit one difference: you have to choose the 2nd card under "Device":
Under "View" --> "Show Summary" you'll see a summary of all running GPUs:
A note on multi-GPU setups:
- works best with Crossfire (or SLI) disabled
- every card needs at least 1 monitor, KVM port or VGA dummy plug connected to it or the GUI miner won't show it under "devices", much like FAH
- mixing different cards in 1 system is not a problem
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What are the "WUs" exactly? What is it all for? How does it work?
to rcofell for the great explanation
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Performance tuning tipps:
- Overclocking your GPU core is very efficient to raise your score, especially on cards like the HD5750/5770/5850
- You can lower your memory clock to save power and keep your card cooler, it doesn't affect hashing performance
- You do NOT need a high bandwidth slot (ie PCIe x16) for optimal performance. In fact, I just ripped open a few x1 slots today and put 5750's in - performance is normal
- there seems to be an issue where the GPU client takes up an entire CPU thread even though it doesn't really do anything, observed primarily on multi GPU setups under Win7 64Bit. Try to use 32bit windows, or Windows XP, or Linux (and report your findings please)
- if your card runs too hot on air cooling, consider lowering the GPU core voltage (only available on some models) or adjusting the fan speed using CCC or MSI Afterburner
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Ok, now that we got it running & producing - what the hell do we do with it?
First off, check your total Mhash rate. Here is a calculator that shows your estimated output if you enter your individual hash rate: http://www.alloscomp.com/bitcoin/calculator.php
It will also show your projected earnings in BCT and USD.
Bitcoin is like a "stock" that changes in value, see here for current exchange rates: http://www.bitcoinwatch.com/
Once you have earned enough, you'll see a balance in your bitcoin core app.
There are several possibilities to "sell" your bitcoins for real money. I haven't tried a lot of them, but here are a few:
https://mtgox.com/
https://bitmarket.eu/ (for us european folks)
https://www.bitcoinmarket.com/
http://bitcoinme.com/
https://www.bitcoin2cc.com/
I'm sure there's a lot more, just try for yourself and report back.
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Problems & solutions
I see that many people are still confused on many things. I am still learning as well, but here are some of the most common issues and how to solve/react to them.
CPU usage is through the roof and/or BOINC is slowing down GUI miner
Your poclbm.exe tasks are using up an entire CPU thread per card? This is a bug that happens mainly on Windows 7 x64 with multiple GPUs. Single GPU miners do not have this problem. 32Bit Windows didn't help for me - WinXP might work. Running Linux definitely helps.
However, there is at least a partial work around: If you lock the affinity of each poclbm.exe instance to the same CPU core (and not all cores), all running miners will share that one CPU thread/core and not use up more than 1 in total. It's not ideal but better than losing 2, 3, 4 etc threads.
If WCG is slowing down the GUIminer, either increase the priority of the running poclbm.exe threads or leave 1 CPU thread/core free via BOINC settings.
I can't connect to a pool, it keeps saying username/password wrong
Make sure you use the worker name which you created on the pool's website as username, NOT your login data to the pool website
I can't connect to a pool, it keeps saying RPC error
The pool might be temporarily down. Or you may be experiencing network trouble. Also make sure port 8332 is forwarded through your various firewalls. Not needed if uPnP is enabled.
The bitcoin core app doesn't want to show any blocks/connections and bitcoin transfers to my wallent don't seem to work either
Make sure port 8332 is forwarded through your various firewalls and/or enable uPnP. BCT transfer will only work correctly once all blocks are connected & shown (currently 128673 blocks, value is increasing so it must show more than that in your bitcoin core client)
Where is my bitcoin credit actually stored? Can I use the bitcoin app to transfer bitcoins on more than 1 computer?
Yes, you can. All your transactions and credit are stored in a file called "wallet.dat". On Win7, it is located under C:\[your username]\AppData\Roaming\Bitcoin. If you want to use your wallet on another computer, simply install the bitcoin core app to that other computer and then copy over your wallet.dat file - done.
Also make sure to back up your wallet.dat file frequently (every 1-2 weeks) so you won't lose your credits in case ur machine crashes!
The address shown in "my bitcoin address" is constantly changing - what does that mean and do I have to change the bitcoin address in my pool's settings to correspond to the new address?
This is normal, and a sort of anonymity feature of the bitcoin network. A new address is usually generated after a successful transfer in order to preserve your anonymity. You can also manually create new addresses by hitting the "new" button next to your current address. But don't worry, payouts will still reach your wallet safely through the old address, so no need to go update the address on the pool all the time.
GUIminer won't start, showing an error message like this: "the application has failed to start because it's side-by-side configuration is incorrect"
I've gotten that error myself on Win 2008 R2. I fixed it by downloading & installing the Microsoft C++ 2008 SP1 x86 library. GUIminer needs it to run, and you need to install the x86 version I just linked even if you are on a x64 OS. Windows 7 users do not need to do this, as C++ 2008 is already there.
GUIminer does start, but it says there are no OpenCL devices detected
Make sure your GPU(s) support OpenCL (ATI HD4xxx and up, Nvidia G80 and newer). If you just installed your brand new ATI drivers and still get the error, try manually installing ONLY the OpenCL part of the driver located at C:\ATI\[...]\Packages\Apps\OpenCL[32/64]\OpenCL.msi
The C:\ATI folder structure is being deployed by executing the Catalyst installer package, so if you don't have it or already deleted it, just re-run the latest Catalyst installer.
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Ok folks, that's all for now - bed time for me.
Just thought you'd like to know. By running what I already had lying around (3x HD5870, 2x HD5770, 1x HD4850) I am currently earning around 25€ a day, increased electricity included. I already converted a few bitcoins to € and yes, it is real - people are using bitcoins to trade, and are actually buying them. For now...
So long
J
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