Network speed unstable

[lucif]

I see spikes from 12T to 30+ and back. And now, on difficulty decrease, it is about 30T again.

Someone has 51%?

[lucif]

http://blockchain.info/pools

[crazyates]

I would like to redirect you to the STICKY at the top of the very page you just posted from: https://bitcointalk.org/index.php?topic=123726.0

[lucif]

Blockchain guessing is just additional info, not main.

The main is: network speed jumps from high to low and back with more than 50% power.

[Luno]

http://bitcoin.sipa.be/speed-lin-2k.png

I see spikes from 12T to 30+ and back. And now, on difficulty decrease, it is about 30T again.

Someone has 51%?

I agree Lufic, statical variation or not, we should have seen a lower average hashrate now. Somebody are bringing hardware on-line in increments. And thanks for that. The price would have collapsed by now if GPU miners keep shutting down, without anyone taking over.

Are there any way to check a block from a solominer to determine if it was mined by an ASIC? Are there some timestamps in the chain to check if it i.e. was mined too fast to have come from a GPU thread? To have some percentage of ASIC's of total hashrate would be neat.

[mrvision]

The price would have collapsed by now if GPU miners keep shutting down, without anyone taking over.

Why? If more miners shut down then less coins would be mined until dificulty is adjusted.
So supply would be decreased until next adjustment.

in the other hand, if asics were in the market they would flood the market of coins until next dificulty adjustment (and correction of the supply)
am i right?

What is your teory?

[Luno]

I'll explain myself:

If network hashrate starts decreasing difficulty decrease will lack behind by 2 weeks. At the same time we have a bunch of unprocessed transactions as some pools don't include them, this will get worse in such a scenario.

Historically difficulty has driven price. That can be changing now however as miners are a smaller part of the economy after halving.

A falling hashrate and longer transaction times, can be seen as Bitcoin decline, which will influence price negatively and give some negative outlook. Me calling it a collapse was a too strong a word, but it will be perceived as a small or larger setback.

[crazyates]

You do realize that those "fluctuations" are just a guessing game to estimate the hashrate, and are VERY subject to luck?

You're looking at the green line, right? The 8 hour estimate? All they're doing is saying: "Hey, in the past 8 hours, the network should have found 48 blocks. What the hell, we only found 41! The network must be crashing!" And at the next 8 hour windows: "Hey, in the past 8 hours, the network should have found 48 blocks. What the hell, we found 63! Someone must be testing ASICs!"

It's VERY subject to luck, and you simple cannot derive that someone is turning mining rigs on and off and on and off simply from an 8 hour window, as the variance naturally caused by luck would more than mask this.

I always go by the 3-day estimate, as a longer time frame would smooth out a large portion of the variance.

[lucif]

I can beleive in luck fluctuations but not with 100% bumps.

I am trader and watching bitcoincharts every day. One day i see 30T network speed at top, another day I see 12T.

This was absent before halving. This is not luck.

[DeathAndTaxes]

I can beleive in luck fluctuations but not with 100% bumps.

I am trader and watching bitcoincharts every day. One day i see 30T network speed at top, another day I see 12T.

This was absent before halving. This is not luck.

No it wasn't absent before the halving and yes it is luck.   Look at the longer averages.  Honestly the 8 hour graph should probably be removed.  There is a huge amount of volatility in that number.  The noise swamps any useful amount of signal.

[lucif]

Am I blind? I didnt saw +/- 100% from day to day in top of bitcoincharts for more than 1.5 years.

[AngelusWebDesign]

Actually, I've had days where my pool got "50%" of the usual amount of blocks in the past 24 hours.

Other times, we're as high as 150% of what we should have found -- or even more.

That's a 100% swing in effective hashrate!

So why isn't that possible on a larger scale?  Of course it is.

[crazyates]

I've seen pools within 5% of luck, or all the way up to 800% of luck. You get a few pools that all have bad or good luck at the same time, and the 8 hour windows starts moving, and quite drastically. Yes, it was there before the reward half, and yes, it's always been quite significant.

Honestly the 8 hour graph should probably be removed.

I agree.

[Graet]

and it has been well established difficulty is affected by price, not the other way round
another thing that affects Bitcoin network hashrate is people chain hopping Litecoin, when difficulty is low and coming back to Bitcoin while it is high, roughly 1Th moves back and forward currently,

[niko]

I see spikes from 12T to 30+ and back. And now, on difficulty decrease, it is about 30T again.

Someone has 51%?

"Network hashrate" is a calculated estimate, not a directly measured quantity. The legend on the graphs says "estimate".  The eight-hour window is expected to contain only 48 randomly-triggered events; this is a small number, and variability can and will appear counterintuitively high to most people.


 

[GernMiester]

This thread explains this phenomenon pretty well and further explains what I suspected with no research done.
I just had no idea that a 8-10Th/s swing was possible at these levels. I knew that charts were screwy but did not dig deep enough to see just how far off the small windows can be.  8-10Th/s still seems to be high but difficulty did just adjust and I am no mathamagician.

[bcpokey]

This thread explains this phenomenon pretty well and further explains what I suspected with no research done.
I just had no idea that a 8-10Th/s swing was possible at these levels. I knew that charts were screwy but did not dig deep enough to see just how far off the small windows can be.  8-10Th/s still seems to be high but difficulty did just adjust and I am no mathamagician.

Look at the purple line, no 8-10TH/sec swings there. If I took the granularity down further, to say 4hours, or 2 hours, you would see even larger swings, reducing time frames until you get to ridiculous levels of 0TH < Network < Inf TH.

I think it is fairly interesting how little change there has been in network hashrate, after the halving, though.

[maqifrnswa]

This thread explains this phenomenon pretty well and further explains what I suspected with no research done.
I just had no idea that a 8-10Th/s swing was possible at these levels. I knew that charts were screwy but did not dig deep enough to see just how far off the small windows can be.  8-10Th/s still seems to be high but difficulty did just adjust and I am no mathamagician.

mathamagician time - number of blocks per time frame follows a Poisson distribution where variance is equal to the expected number of blocks. So 48 blocks in 8 hours means that you can expect +/- 7 blocks pretty frequently. So +/- 15% is no big deal and extremely common. At 20 TH/s, it is extremely common to see it fluctuate from 17 to 23 TH/s (6 TH/s swing) and common enough to see it fluctuate +/- 30% (from 14 to 26 TH/s).


Note: if total network hashing power decreases rapidly and difficulty remains the same, you'd see an even larger relative variance since you'll have even fewer blocks per time period.