Is that normal for my S5 to have their share rate (hash rate) fluctuate that much compared to my S3+ ?
Average is 1.15Th as expected so it's generally ok, and I understand that even though fluctuation is within a 10% for both, graph seems less regular for S5's because they have a higher hashrate.
https://i.imgur.com/fiXdKTT.jpg
I will add 2 S5 and 2 S3+ next week when I come back from easter holidays.
I just have to calculate Amp and spread them on the proper power lines/plugs.
Higher diff will get higher variance on the same device, and in general will for any device since you are aiming for a higher share target.
It really is the red line and the "Your N Avg" on the rewards page that matters, not the variance.
Remember also that some shifts are really short when we find a block, so of course the chance of higher variance exists.
I actually have a spike up on my graph that is about 20% for one short shift recently when we found a block.
It is all random also though, so sometimes on very short shifts you'll get a spike up and sometimes a spike down.
... and a relevant statistic on the subject
ckpool sets the diff so that the average should be close to 18 shares per minute, i.e average (over time) around 10/3 seconds per share.
But share finding is just the same random poisson distribution as block finding.
So using some of that table I often post bits of:
0.63212055882856 100.000% 1 in 2.7
0.86466471676339 200.000% 1 in 7.4
0.95021293163214 300.000% 1 in 20.1
0.98168436111127 400.000% 1 in 54.6
0.99326205300091 500.000% 1 in 148.4
0.99752124782333 600.000% 1 in 403.4
0.99908811803445 700.000% 1 in 1096.6
0.99966453737210 800.000% 1 in 2981.0
0.99987659019591 900.000% 1 in 8103.1
i.e. firstly, you expect to get, on average, about 8100 shares in 8100*10/3 seconds - ~7.5 hours
... and you expect, on average, one of those shares every ~7.5 hours to take 900% = 9 x 10/3 = 30 seconds.
Yep about 3 times a day, on average, your miner will take more than 30s to find it's next share.
If you happen to have bad luck and get a few of those long shares in the same shift then of course you'd expect that shift point to be below the red line.
Of course the reverse is also true of quick shares, sometimes you'll get way more than 18 shares per minute and if you get a lot of them in a single shift it will be above the red line.
Simple answer: variance is expected, and it should average out over time.