Latest posts of: kislam

This question gets asked by every miner at the beginning when they are testing the waters with bitcoin mining. A lot of great pools are out there and at the end of the day it boils down to your personal choice. There is really no single best pool, but there is most likely a pool that is right for you, based on _your_ requirements and preferences. This guide won’t tell you which pool is best, but it will help you choose one according to your own liking.

(This guide is more suitable for miners with a limited hashing power, those who are at the beginning stages of their bitcoin mining commitments or those who consider themselves to be casual miners. Hardcore miners, especially those with multi-GHash rigs already know all there is to know about different pools and have already figured out what works for them.)

Before I go into more detail, please note that there are at least two pretty comprehensive lists of pool features available to you (at least that I know of):

The mining pools feature table (https://bitcointalk.org/index.php?topic=12920.0)
Comparison of mining pools (https://en.bitcoin.it/wiki/Comparison_of_mining_pools)

You should read up on the above information before you go through this guide. While these places are excellent sources of information, they can be a bit overwhelming for the beginner, hence my effort to ease things a bit by providing a subjective guide below.

I found that the following factors were most important for me in choosing the right pool:

What is the reward method – Proportional/Pay Per Share/Score Based/PPLNS
What fee they charge for mining and withdrawal of funds
How frequently they find a block (means how frequently I get rewarded)
How easy it is to withdraw funds
What kind of stats they provide
Do they offer BTC + NMC merged mining?
How stable is the pool?

What you need to do is sort the above points according to importance as per your personal preference and then use them to prune out the pools that do not meet your required criteria. For example, my top requirement at the moment is merged mining, since it offers 10% to 13% more reward at the moment without any extra effort on my part. So pools that do not offer merged mining automatically get pushed to second tier in my list no matter how well they do in other areas.

Important: _Always_ set up one or more backup pools in your mining software (all major miners offer this option, please consult their respective threads for instructions if you need help). Even the most robustly setup pools can experience downtimes for various reasons, so your miner will be left without any work if something like that happens when you are AFK.

So here goes…

Pool Reward Method: Different pools follow different reward methods (note: ‘reward’ is what you earn when you mine with a pool, as opposed to ‘payout’, which is the amount you withdraw from the pool after you have generated some reward). Different reward methods are discussed in the above link for ‘Comparison of mining pools’ link provided above, so go read up. The most common are :
   o   Proportionate – where you get paid an amount proportional to the number of shares you submitted compared to the total number of shares in that round,
   o   Pay-per-share – where you get paid a fixed amount per share you submit regardless of the length of the round,
   o   Score-based – where your rewards are calculated based on the score the pool assigns you, which quickly diminishes as soon as you stop mining,
   o   PPLNS – where only the last N shares are considered to calculate your reward

There are other variants as well, notably the SMPPS method used by Eligius. What you need to know in reality is how the above methods impact your rewards. If you are a casual miner who mines occasionally or if you run a rig that for some reason cannot maintain a stable connection with the pool (bad internet, hardware problems, miner freezing up, etc. etc.), then score-based and PPLNS pools require special consideration on your part. Score-based pools punish the miner who, for whatever reason, does not or cannot maintain a stable mining operation at the pool for the entire duration of the round. If mining with slush, for example, getting disconnected for just 5 minutes will reduce your score to virtually zero and if they find a block at that time, you get paid nothing, even though you mined with them for the last 4 hours. On the other hand, you get paid in full if you are lucky enough to join slush just 5 (or maybe 10? I somehow feel that it takes longer to build up score than to diminish it) minutes before they solve a block even if that round has been running for several hours. The average reward will even out over the long run, but that also means you will need to stick to that one pool over an extended period in order to reap the expected reward. A key requirement for intermittent miners is knowing how much reward they are getting for whatever length of time they do manage to mine, which score-based and PPLNS (and other fancy variants) do not allow. It is better, in my opinion, to stick to zero-fee PPS pools in this case since you get the expected reward whenever you mine.

Pay-per-share and proportionate pools do not have the intermittent issue and you can mine with them on and off and get paid for whatever work you have done for them. Proportionate pools have higher variance than others, meaning that for short rounds you get paid a lot, but for long rounds you get paid much less. Since you get paid in proportion to the number of shares you submitted, if your hashing power is 1% of the pool, you get paid 50 cents for an hour-long round (less any pool fees). You also get that same 50 cents if the round lasts for 10 hours, so you get the picture. Proportionate pools are also a prime target for pool hoppers, which can reduce the actual reward you earn.
Pool Fees: There are zero-fee pools and there are pools that charge a fee for mining with them. Pool fees are not necessarily a bad thing – it’s usually worth it to pay the fee in exchange of the benefits they offer. Deepbit charges 3% fee for proportionate mining, but they pay for invalid blocks. But if you are adamant not to pay any fee, you can still find pools that charge nothing or almost nothing to mine with them. Please note that not all pools clearly declare their fee structures, especially Pay-per-share pools that only declare how much they pay for each share, and you have to calculate the pool fee from that information (this is fairly simple, btw, you just find the current theoretical value per share by dividing 50 by the current difficulty, then subtract the pool’s declared pay-per-share value to find the pool’s fee). You can find summary of pool fees in the links provided above.
Pool Speed: The more GHash the pool has, the faster they will find blocks. Deepbit, with their current speed of 3328 GHash/s, seems to find 2 blocks per hour in average. Smaller pools can take days or weeks to find a block. You will roughly get the same total reward over an extended period from faster and slower pools, but whether you will have the patience to wait for days for your reward (especially if you are a sub-GHash miner and your rewards are small), is completely up to you.
Fund withdrawal/Payout: Do you want your rewards to be automatically sent to your wallet? Do you want an option to send out funds to your wallet as and when you feel necessary? Different pools have different payout policies that you may want to review from the ‘The mining pools feature table’ link provided above. Some pools, like slush, only give you the option for automatic payouts once the confirmed reward crosses the payout limit you have set. Eligius automatically sends your payout when your reward crosses approximately 0.67108864 BTC or after one week of inactivity. This may be a deal breaker for miners with small hash-power, as with a 300 MHash rig mining continuously you will have to wait 3 days before you get a payout. On top of that, once you do receive a payout from eligius, you have to wait for 120 confirmations (takes about 18 hours in my case) before your bitcoin client will let you spend it.
Other pools let you withdraw funds whenever you feel like it once you have enough confirmed rewards in your account. They usually impose a minimum amount of reward, which is generally very low, like 0.01 BTC, but for NMCBit the minimum is 0.10 BTC. These limits are not usually declared and you find out only when you try to withdraw funds. Some pools let you withdraw the full amount in your account, but some, like Bitcoins.lc, only let you withdraw up to two decimal points.
While some pools let you withdraw funds as soon as a block is solved, others make you wait for 100 or 120 confirmations of the block before you can withdraw those funds. More details about this can be found at the links provided above.
Pool Stats: Some pools provide awesome graphs and statistics of your mining records with them. Others provide very few stats, the rest are in between. ARS offers fantastic stats, ABCPool offers great stats as well, but for a fee. Eligius is very frugal with stats. Slush and deepbit are somewhere in between, although slush offers performance graphs where deepbit doesn’t. How important detailed stats are depends completely upon your personal preference, so you need to shop around a bit in this regard.
Merged Mining: At present this is quite a nice addition when a pool offers merged mining. What this basically means is that you continue mining like you always do, but the pool gives you extra Namecoins for the same amount of mining and you can at the moment exchange those namecoins at an exchange (the going rate at bitparking is ~0.0104 BTC per namecoin). Since current Namecoin difficulty is much lower than Bitcoin, you essentially earn about 10% extra with the same hashrate, which is a big plus. Some pools like NMCbit even offer the option to directly convert namecoins to bitcoins without having to go through an exchange, but they (seem to) charge a fee that is not clearly declared (i.e. they were offering 0.01 BTC per NMC when the going rate at bitparking was 0.011 BTC per NMC).
Pool Stability: You (naturally) want to get the most out of your mining. Some pools offer better stability, less stales than others. This status keeps changing as pools keep improving themselves. On the other hand, great pools can temporarily become unattractive due to factors like DDoS attacks and server migrations. You need to find out more by reading up on the most recent posts in their own forums or in their respective threads in this forum.

At some point after you take mining seriously (or maybe just browsing the forum), you will come across the idea of pool hopping. It’s basically a technique used by some miners to reap extra rewards by exploiting ‘flaws’ in reward methods, especially the proportionate reward method (although other reward methods like score-based have been proven hoppable, proportionate is claimed to be the easiest to hop). The extra rewards they collect come from other miners that are not hopping. Whether this is ethical or not is beyond the scope of this discussion (you will find quite a few discussions regarding the ethics of pool hopping, feel free to make up your own mind about it). Many pools these days actively discourage, or even ban pool hoppers. Others implement hop-proof reward methods like PPLNS or Pay-per-share. I am not going to tell you whether you should or should not become a pool hopper, it is entirely up to you. But you should avoid proportionate pools that do not take adequate measures to deter pool hoppers, since it will reduce your rewards.

So, that’s some of the things you need to consider while choosing the right pool for you. As I have mentioned before, it all comes down to your own personal preferences. I have just tried to make it easier for you to make sense of all the info available about the pools in their websites as well as this forum. Good luck and happy mining.

Comments, suggestions, corrections are highly welcome.

[Edit]: I have modified the pool reward section.