I'm earning about half the BTC I should get at BTCGuild. What's going wrong?

[Ali]

I'm unly running a very small rig (6950 = 250 Mhashes/s).

On BTCGuild I got around 0.088 BTC per day.
According to mining-calculators I should get at least 0.14 BTC at the current difficulty. Any ideas what's going wrong?

That step is pretty important because at a price of 22 euro-cent per kw/h mining is already not profitable anymore at 0.088 BTC / day.

[nafai]

btcguild has been very unlucky lately.  Actually, most of the pools have been very unlucky lately.

[smoked_out]

I'm unly running a very small rig (6950 = 250 Mhashes/s).

On BTCGuild I got around 0.088 BTC per day.
According to mining-calculators I should get at least 0.14 BTC at the current difficulty. Any ideas what's going wrong?

That step is pretty important because at a price of 22 euro-cent per kw/h mining is already not profitable anymore at 0.088 BTC / day.

Could be Variability. Some days you make less some more then calculator. Also Monitor your miner, make sure he is running 100% all day long. Deepbit and miningmonitor both have stats for this

[Ali]

Ah, I see.

I'm already using miningmonitor.com. It shows that the rig has been up for 95% of the time.

[Jack of Diamonds]

Your problem is that you're using a proportional pool.
In the short term both variance and pool hoppers can eat away at your earnings with no shame.

Use a PPS pool or a PPS variant if you want to get paid the same amount day in, day out regardless of good/bad luck of the pool

[compro01]

BTCguild has been having lousy luck today.  the 24 hour luck is sitting at -35.8%.

though things look to be improving.  it was below -50% earlier today.

[Ali]

Good idea. I still think the number of pool-hoppers is relatively small.

I used to be on Eligius but it had all these server-problems. Seems stable now.

Also can you recommend some hardware which offers a nice Mhash/J-value?

I don't trust the values on the mining hardware comparison table much.

[hugolp]

We had a user that brings bad luck to the poll. He left as a sacrifice for the rest, and as soon as he left BtcGuild has satrted having great luck. The gods of the mines were pleased with the sacrifice.

http://forum.bitcoin.org/index.php?topic=7760.msg397575#msg397575

[sequence]

What exactly is the luck part about? 

[aq]

Your problem is that you're using a proportional pool.
In the short term both variance and pool hoppers can eat away at your earnings with no shame.

Use a PPS pool or a PPS variant if you want to get paid the same amount day in, day out regardless of good/bad luck of the pool

Keep in mind, that while good/bad luck averages out over just a few days, one has to constantly pay the 10% fee of a PPS pool...

[Jack of Diamonds]

Eligius and mineco.in have 0% though it's not pure PPS, their balance is positive enough for anyone to switch there, you are guaranteed 100% of your expected earnings daily as long as the server is up & the buffer stays positive

Also RFCpool has 7% pps, and btcpool24.com has 0% pps (I have mined at the latter for ~50k shares but didn't trust the operator enough so I quit after some hours, there are strong hints he is an amateur or does not know what he is doing)

[kjj]

What exactly is the luck part about? 

Mining is really a lottery.  Each hash calculated has a 1 in 7.26 quadrillion chance of winning (right now).  BTC Guild is currently running around 2.4 billion hashes per second, so it should expect a win every 3000 seconds or so, which is around 50 minutes.

But since it is a lottery, there is no promise of winning.  A block may be found after a minute, or after several hours.  The deviation away from the statistical expectation is the "luck".