It should pay 100USD for every 713 shares (diff as I type).
That refers to shares of a certain difficulty: diff 1 Litecoin shares or diff 65,536 shares according to some mining clients (notably CGMiner).
Each found share has its difficulty. If the share's difficulty is equal to or higher than the worker's difficulty, it gets submitted by the worker and accepted by the pool.
At 713 difficulty, it will take on average 713 * 65,536 = 46,727,168 diff 1 shares to find a block. Likewise, it would take 713 * 65,536 / D diff D shares.
Note that, if you submit a diff 256 share at 128 worker difficulty, you get paid for a diff 128 share. So, assuming your worker difficulty is constant (LTC pools tend to use variable difficulty), your expected payout would be numbers of shares * worker difficulty * 50 / difficulty LTC, where both worker difficulty and difficulty should use the same metric (just use the values the mining client reports).
Aren't the mechanisms supposed to be very similar?
For Bitcoin mining, a diff 1 share (lowest possible worker difficulty) is found for every 232 hashes that are calculated. Since Litecoin's scrypt algorithm is about 1000 times slower than SHA256, mining Litecoins would have a very high variance if the same metric of worker difficulty was being used.
Therefore, pools and mining clients implemented shares with worker difficulty lower than 1, e.g., diff 2-10.
In order to avoid dealing with fractional difficulties (I assume), mining clients labelled diff 2-16 shares diff 1 shares, so actual diff 1 Litecoin shares become diff 65,536 shares.
Litecoin difficulty is very low!
Since computing hashes is 1,000 times slower for Litecoin mining, a difficulty of 713 for Litecoin mining is more or less equivalent to a difficulty of 713,000 for Bitcoin mining.
2If you're getting 100Mh/s on bitminter with ltc you wont get the same, if thats what you base all your calculations on since ltc uses scrypt which is memory hard – Enthusiast – 2013-06-17T06:07:16.867
Correct me if I am wrong but what matters is the number of shares accepted right? I may be getting 1000x more hashes on Bitcoin than on Litecoin but the number of shares/minute is pretty similar. I know that you need 2^32 hashes in average to find a share on BTC, do you have any idea of what that number is for LTC? – Thiago – 2013-06-18T01:24:08.253
So just to clarify, you're doing 4 shares a minute on a litecoin pool? Which pool is it or at what difficulty are those shares? That would allow us to actually calculate your effective scrypt mining performance and your chances of finding a block (which is then shared with the pool and you get your shares worth). – cdecker – 2013-06-18T18:42:28.297
to compare relative profitability, try dustcoin.com
– leximus prime – 2013-06-18T21:30:58.377Right now I"m actually doing 14 shares a minute on Pooled Bits. With difficulty now at around 746, I should be getting a block every 53 minutes. There's clearly something wrong because I couldn't and I'm not! – Thiago – 2013-06-22T23:09:17.853
@Tom: The number of hashes needed to find a share is up to the pool. Some of them automatically tune the share difficulty to keep the rate at which shares are found roughly constant for each miner. – David Schwartz – 2013-06-24T18:19:15.910
based on what do they do this calculation? – Thiago – 2013-06-27T02:41:57.387
And litecoin difficulty is NOT very low. – None – 2013-06-26T16:42:58.217