At Frontier, the first release of Ethereum, you'll just need a) a GPU and b) an Ethereum client, Geth. CPU mining will be possible but too inefficient to hold any value.
At the moment, Geth only includes a CPU miner, and the team is testing a [GPU miner branch](https://github.com/ethereum/go-ethereum/tree/gpu_miner), but this won't be part of Frontier.
The C++ implementation of Ethereum also offers a GPU miner, both as part of Eth (its CLI), AlethZero (its GUI) and EthMiner (the standalone miner).
_**NOTE:** Ensure your blockchain is fully synchronised with the main chain before starting to mine, otherwise you will not be mining on the main chain._
When you start up your ethereum node with `geth` it is not mining by default. To start it in mining mode, you use the `--mine` [command line option](../interface/Command-Line-Options). The `-minerthreads` parameter can be used to set the number parallel mining threads (defaulting to the total number of processor cores).
`geth --mine --minerthreads=4`
You can also start and stop CPU mining at runtime using the [console](../interface/JavaScript-Console#adminminerstart). `miner.start` takes an optional parameter for the number of miner threads.
```
> miner.start(8)
true
> miner.stop()
true
```
Note that mining for real ether only makes sense if you are in sync with the network (since you mine on top of the consensus block). Therefore the eth blockchain downloader/synchroniser will delay mining until syncing is complete, and after that mining automatically starts unless you cancel your intention with `miner.stop()`.
In order to earn ether you must have your **etherbase** (or **coinbase**) address set. This etherbase defaults to your [primary account](Managing-your-accounts). If you don't have an etherbase address, then `geth --mine` will not start up.
You can set your etherbase on the command line:
```
geth --etherbase 1 --mine 2>> geth.log // 1 is index: second account by creation order OR
Note that your etherbase does not need to be an address of a local account, just an existing one.
There is an option [to add extra Data](../interface/JavaScript-Console#adminminersetextra) (32 bytes only) to your mined blocks. By convention this is interpreted as a unicode string, so you can set your short vanity tag.
```
miner.setExtra("ΞTHΞЯSPHΞЯΞ")
...
debug.printBlock(131805)
BLOCK(be465b020fdbedc4063756f0912b5a89bbb4735bd1d1df84363e05ade0195cb1): Size: 531.00 B TD: 643485290485 {
See also [this proposal](https://github.com/ethereum/wiki/wiki/Extra-Data)
You can check your hashrate with [miner.hashrate](../interface/JavaScript-Console#adminminerhashrate), the result is in H/s (Hash operations per second).
```
> miner.hashrate
712000
```
After you successfully mined some blocks, you can check the ether balance of your etherbase account. Now assuming your etherbase is a local account:
```
> eth.getBalance(eth.coinbase).toNumber();
'34698870000000'
```
In order to spend your earnings you will need to have this account unlocked.
```
> personal.unlockAccount(eth.coinbase)
Password
true
```
You can check which blocks are mined by a particular miner (address) with the following code snippet on the console:
```
function minedBlocks(lastn, addr) {
addrs = [];
if (!addr) {
addr = eth.coinbase
}
limit = eth.blockNumber - lastn
for (i = eth.blockNumber; i >= limit; i--) {
if (eth.getBlock(i).miner == addr) {
addrs.push(i)
}
}
return addrs
}
// scans the last 1000 blocks and returns the blocknumbers of blocks mined by your coinbase
// (more precisely blocks the mining reward for which is sent to your coinbase).
minedBlocks(1000, eth.coinbase);
//[352708, 352655, 352559]
```
Note that it will happen often that you find a block yet it never makes it to the canonical chain. This means when you locally include your mined block, the current state will show the mining reward credited to your account, however, after a while, the better chain is discovered and we switch to a chain in which your block is not included and therefore no mining reward is credited. Therefore it is quite possible that as a miner monitoring their coinbase balance will find that it may fluctuate quite a bit.
The logs show locally mined blocks confirmed after 5 blocks. At the moment you may find it easier and faster to generate the list of your mined blocks from these logs.
Mining success depends on the set block difficulty. Block difficulty dynamically adjusts each block in order to regulate the network hashing power to produce a 12 second blocktime. Your chances of finding a block therefore follows from your hashrate relative to difficulty. The time you need to wait you are expected to find a block can be estimated with the following code:
**INCORRECT...CHECKING**
```
etm = eth.getBlock("latest").difficulty/miner.hashrate; // estimated time in seconds
Given a difficulty of 3 billion, a typical CPU with 800KH/s is expected to find a block every ....?
# GPU mining
***
## Hardware
The algorithm is memory hard and in order to fit the DAG into memory, it needs 1-2GB of RAM on each GPU. If you get ` Error GPU mining. GPU memory fragmentation?` you havent got enough memory.
The GPU miner is implemented in OpenCL, so AMD GPUs will be 'faster' than same-category NVIDIA GPUs.
ASICs and FPGAs are relatively inefficient and therefore discouraged.
The official Frontier release of `geth` only supports a CPU miner natively. We are working on a [GPU miner](https://github.com/ethereum/go-ethereum/tree/gpuminer), but it may not be available for the Frontier release. Geth however can be used in conjunction with `ethminer`, using the standalone miner as workers and `geth` as scheduler communicating via [JSON-RPC](https://github.com/ethereum/wiki/JSON-RPC).
The [C++ implementation of Ethereum](https://github.com/ethereum/cpp-ethereum/) (not officially released) however has a GPU miner. It can be used from `eth`, `AlethZero` (GUI) and `ethMiner` (the standalone miner).
[You can install this](https://github.com/ethereum/cpp-ethereum/wiki/Installing-clients) via ppa on linux, brew tap on MacOS or from source.
`ethminer` communicates with geth on port 8545 (the default RPC port in geth). You can change this by giving the [`--rpcport` option](https://github.com/ethereum/go-ethereum/Command-Line-Options) to `geth`.
Ethminer will find get on any port. Note that you need to set the CORS header with `--rpccorsdomain localhost`. You can also set port on `ethminer` with `-F http://127.0.0.1:3301`. Setting the ports is necessary if you want several instances mining on the same computer, although this is somewhat pointless. If you are testing on a private cluster, we recommend you use CPU mining instead.
Also note that you do **not** need to give `geth` the `--mine` option or start the miner in the console unless you want to do CPU mining on TOP of GPU mining.
If the default for `ethminer` does not work try to specify the OpenCL device with: `--opencl-device X` where X is 0, 1, 2, etc.
When running `ethminer` with `-M` (benchmark), you should see something like:
