New diff thread Jan 27th to Feb 11 (-5.73%) to (+0.09%)

[philipma1957]

this means someone (bitfury?)  could have turned off 50ph last adjustment to create a 6% drop and now has turned it back on since the diff will stay low for 11 -12 days.

Much more likely is that this was variance; +/-6% differences due to variance are surprisingly likely: http://hashingit.com/analysis/28-reach-for-the-ear-defenders

If I get a spare few hours over the next week I'll actually calculate the PDFs/CDFs for the spectrum of variance percentages.

Today's large spike is well within the norms for a 24 hour variance. In fact if you look at the last 2 years of daily hash rates on a log scale then it's pretty clear that there's nothing particularly unusual about what's been happening recently. There have been many similar runs of good and bad luck in the past: https://blockchain.info/charts/hash-rate?timespan=2year&showDataPoints=false&daysAverageString=1&show_header=true&scale=1&address=

The recent changes look much more erratic because they're referenced to a baseline of closer to 2% as opposed to ones that were references to perhaps 15%.

most likely you are correct.  but we finally have conditions  for someone to power up then power down gear.  or over and underclock gear.

1) Cex.io has a lot of hashpower they turned off.--------they said this not us.
2) growth is pretty flat
3) price is low

[klondike_bar]

I much prefer a good conspiracy theory. Does certainly feel like the big boys toying with the diff.

Or perhaps someone bought a load of these 100ghs stick miners:

http://aryadutaminer.com/cheap-the-bh-miner-usb-bitcoin-100ghs-sha26-miner-and-free-shipping.html

seriously that site looks so dodgy

while hashingit.com is brill.

haha that site is gold.

 

BH Miner USB Bitcoin

 No. of chips: Minion ASIC chips SHA26,
 Hashrate: ~100GH/s out of the box, up to 120GH/s overclocked,
 Power usage: ~0.75W per GH,
 Dimentions: 28x60mm without usb plug,
 Voltage: 5V
 Power requirement: 2-2.5A
 Supported software: cgminer

(100gh)(0.75w/gh) = 75W
(75W)/(5V) = 15A

not sure how you pull 15A over a usb port, since that's 6X the advertised power usage. The 14 reviews of it being a good, fast-delivered product (and stating it does 100GH+) is the icing on the scam-cake

heres a 1200MH scrypt miner that looks a lot like a fancy ATX pc   http://aryadutaminer.com/buy-the-blessinghash-leopard-1200mhs-scrypt-miner-online.html

[davejh]

I much prefer a good conspiracy theory. Does certainly feel like the big boys toying with the diff.

Or perhaps someone bought a load of these 100ghs stick miners:

http://aryadutaminer.com/cheap-the-bh-miner-usb-bitcoin-100ghs-sha26-miner-and-free-shipping.html

A SHA26 miner seems like it's short-changing everyone - I want to know when they'll deliver the other 230 to make the full SHA256? I'm particularly impressed by the offer to buy 1000 of them for the discount price of $73440. Shame the domain has only been up for 14 days! You'd hope that at the very least they'd make it an offer that was too good to be true?

while hashingit.com is brill.

One of these days I may even manage to come up with a site design that doesn't look like it escaped from the early 90s! 

[adaseb]

I just don't understand why some big player would turn off all his gear for a few days just to make the difficulty go down by 6%. Won't he lose more money in the long run? Since turning gear off for 2-3 days would be a higher loss then mining at a slightly higher difficulty.

Need someone to run the math on this.

[philipma1957]

I just don't understand why some big player would turn off all his gear for a few days just to make the difficulty go down by 6%. Won't he lose more money in the long run? Since turning gear off for 2-3 days would be a higher loss then mining at a slightly higher difficulty.

Need someone to run the math on this.

if his gear was 1.0 watt gear or .8 watt gear  a 6% shift in price turns gear in or out of the black.


example network = 300 ph     20 ph is just about 6%  

when gear jumped from       290ph to 314 ph price dropped a bit and having 1 watt gear may have been a loser.

 https://bitcoinwisdom.com/bitcoin/difficulty

Difficulty History

Date   Difficulty   Change   Hash Rate
Jan 27 2015   41,272,873,895   -6.14%   295,442,739 GH/s

Jan 12 2015   43,971,662,056   8.20%   314,761,417 GH/s

Dec 30 2014   40,640,955,017   3.00%   290,919,288 GH/s


In bold  diff got to 43.9.  So I have a big ass dragon farm all 1 watt gear.

when diff was 43.9 and coins were 209.82  that 1 watt per gh farm did not earn on 10 cent power it lost.

So I turned it off.

Diff drops to 41.9 price jumps to 235 that same farm makes money.

10 cent power-- 1 watt gear ---diff of 43.9 ---- coins at 209 a loser.  price got under 180 during this time period so even if he had cheaper power then 10 cents he was losing money.





full size image
http://imageshack.com/a/img537/6989/d9lF24.png

10 cent power--- 1 watt gear -- diff of 41.9---- coins at 234 a winner.  since diff dropped and price jumped why not turn it on make some money.



full size image
http://imageshack.com/a/img537/3668/CFKoMx.png

[judypug1956]

It does not mean anyone is doing it.  Most likely it is not 1 giant player .  More like a few hundred people with 10 th to 1 ph setups.

When that price was under 190 and diff was up to 43.9 people power off.

 What I am saying is this is the first time on paper you can show a big player can do this.  
 I see this happening over and over and over for the next 2 to 5 months. In fact with out a strong push on BTC price upwards or down
this could happen for a long time.

[adaseb]

I just don't understand why some big player would turn off all his gear for a few days just to make the difficulty go down by 6%. Won't he lose more money in the long run? Since turning gear off for 2-3 days would be a higher loss then mining at a slightly higher difficulty.

Need someone to run the math on this.

if his gear was 1.0 watt gear or .8 watt gear  a 6% shift in price turns gear in or out of the black.


example network = 300 ph     20 ph is just about 6%  

when gear jumped from       290ph to 314 ph price dropped a bit and having 1 watt gear may have been a loser.

 https://bitcoinwisdom.com/bitcoin/difficulty

Difficulty History

Date   Difficulty   Change   Hash Rate
Jan 27 2015   41,272,873,895   -6.14%   295,442,739 GH/s

Jan 12 2015   43,971,662,056   8.20%   314,761,417 GH/s

Dec 30 2014   40,640,955,017   3.00%   290,919,288 GH/s


In bold  diff got to 43.9.  So I have a big ass dragon farm all 1 watt gear.

when diff was 43.9 and coins were 209.82  that 1 watt per gh farm did not earn on 10 cent power it lost.

So I turned it off.

Diff drops to 41.9 price jumps to 235 that same farm makes money.

10 cent power-- 1 watt gear ---diff of 43.9 ---- coins at 209 a loser.  price got under 180 during this time period so even if he had cheaper power then 10 cents he was losing money.





full size image
http://imageshack.com/a/img537/6989/d9lF24.png

10 cent power--- 1 watt gear -- diff of 41.9---- coins at 234 a winner.  since diff dropped and price jumped why not turn it on make some money.



full size image
http://imageshack.com/a/img537/3668/CFKoMx.png

I see. But it seems that having 20PH/s results in very little money ($500 in 10 days). Seems that eventually the farm might just sell off the hardware .

[SunnyIgor]

more like 400 btc

[davejh]

I just don't understand why some big player would turn off all his gear for a few days just to make the difficulty go down by 6%. Won't he lose more money in the long run? Since turning gear off for 2-3 days would be a higher loss then mining at a slightly higher difficulty.

Need someone to run the math on this.

No-one would do this - all of the conspiracy theories about this happening are exactly that, theories. The only time it would make sense to turn hardware off and then back on again is if the BTC price suddenly jumped and that old hardware would turn a profit again.

My favourite version of this theory was the one where we'd see large dips (again quite statistically normal) just before the end of a difficulty period when in practice the impact of such dips was actually very small on the difficulty change and the losses from losing 2 or 3 days of mining necessary to make those dips would be huge.

Most large scale miners have contracts for power that mean that they pay for a set amount of power whether they use it or not. The only time they'll turn things off is when they're shutting down that particular operation completely, or if they're replacing the equipment with something newer and more power efficient.

Smaller-scale miners probably will act differently because they're generally not going to be tied to contracts on power usage, but that's also one of the reasons that they end up paying (on average) more than the large scale operations.

The real problem is that there's no highly accurate way to measure the hash rate. It's always inferred from the block finding rates, but they're highly erratic because they're a Poisson process. If we could get all of the difficulty 1M share data then we could get dramatically more accurate numbers and that would make sense within a few tens of minutes, but unfortunately there's no accurate way to get this across a large enough fraction of the mining network.

[philipma1957]

...
I see. But it seems that having 20PH/s results in very little money ($500 in 10 days). Seems that eventually the farm might just sell off the hardware .

yes the profit would be low. but a big place is not going to run at a loss.  So turning the gear off when they were losing money makes sense.

Last diff was 43.9 and price got to 170 usd . Shutting off a farm that was losing money is rational.

then making an effort to sell it off makes sense.  If selling the gear proves to be tough slow or hard which it would be exactly that.

If diff moved to 41.9 and price jumped to 240 which is what it did why not turn your gear back on make some money while you try to sell it off?

These conditions have just occurred it does not mean one big player did this.
 It does mean as far as I remember it makes money sense to have this happen.

As davejh says variance  is the culprit.  He certainly can be right but the money conditions and the diff conditions are so that the conspiracy theory has financial  logic. This does not mean he is wrong if you look today the numbers are shifting again to make his variance case stronger.

[BTCish]

It may be a little % raising in this period.

[alh]

My guess for the difficulty increase is:

1.95%

[skuser]

My estimate:
+2.00%

[philipma1957]

I think I am going to change my guess on monday or tue.  

btc price is 229  this price still allows for my mythical big player to run his 1 watt gear at a profit and offer it for sale to others with free or close to free power.  Have to think this will put us into the plus this adjustment

[suchmoon]

I think I am going to change my guess on monday or tue.  

btc price is 229  this price still allows for my mythical big player to run his 1 watt gear at a profit and offer it for sale to others with free or close to free power.  Have to think this will pus us into the plus this adjustment

Just to remind you and everyone else - deadline for the bounty is Sunday, Feb 1st 16:00 UTC (about 22 hours from the time of this post).

Countdown: http://www.tickcounter.com/countdown/20150201040000pm/w5310/1/BTC_difficulty_guess_bounty

As of now:

philipma1957 - 2.82%
SimplisticStu -3.58%
railzand  -3.00%
BTCish -2.00%
klondike_bar +0.00%
mavericklm -0.01%
notlist3d -2.50%
tarmi -1.24%
Kexkey -0.27%
SunnyIgor -3.20%
wpt1wpt1 +3.20%
stonerider +0.10%
davejh +5.50%
tsm13 -2.24%
alh +1.95%
skuser +2.00%

[SimplisticStu]

I would like to revise my guess to +0.75% please 

[notlist3d]

Bitwisdom:

Bitcoin Difficulty:    41,272,873,895
Estimated Next Difficulty:    41,550,720,464 (+0.67%)
Adjust time:    After 1348 Blocks, About 9.0 days

Definitely a positive change.

[buyandhold]

could I say +5.99% please

[armedmilitia]

Gonna take a stab at this.

3% increase, give or take a percent.
So far I'm 1/1 on my predictions, lets see if I make it 2/2!  

[philipma1957]

We  have about 16 hours to change our guess. Or do our first guess.