https://bitcointalk.org/index.php?topic=5059817.msg53174391#msg53174391

Quote from: kerney666

We will shortly release a Ethash miner testing tool, it's just a simple open source node.js project. You will be able to run controlled long-running tests on all miners. The reason this is important is that the displayed hashrates of Claymore and Phoenix are just bullshit. They both add +1.5% or more of fake hashrate. I don't ask anyone to buy these claims without being able to verify it themselves though, which is why we'll release the tool (which acts as a low diff fake pool with a static epoch and controlled job update mechanism) and everyone can see for themselves if they are willing to mine air for ~24h. To verify that we're not insane, we've also reverse engineered both miners, analysed their kernels, traced their OpenCL enqueue calls, and the evidence is clear.

Plenty of people have already pointed this out just by logging all shares over time, but it's really hard to prove anything. You need controlled runs of (preferably) 1 million shares, which is more or less impossible without controlling the environment properly. Another simple way is just to find a big farm from e.g. the frontpage of ethermine.org (found blocks) and check the difference between their reported and accepted hashrate.

Here is one example: https://ethermine.org/miners/6F714AaAAF72977267601cC1cADC49fb3966Ff89/dashboard

Reported: 3.206 TH/s, Accepted: 3.111 TH/s, difference -2.97%. I'm fairly certain this is Phoenix miner. Why do we have a diff of -3%? The dev fee is 0.65%, and there are 1% stale shares, and this is a HUGE sample set that should converge nicely. Contrary to what people seem to believe, the additional -1.35% just should _not_ disappear. For comparison, here is a run using our soon-to-be-released testing tool for 247k shares on Phoenix 4.7c:

Code:

Hashrates for 1 active connections:
   Global hashrate: 228.51 MH/s vs 235.43 MH/s avg reported [diff -2.94%] (A247366:S1575:R0 shares, 93582 secs)
   Global stats: 99.37% acc, 0.63% stale, 0% rej.
   [1] hashrate: 228.51 MH/s vs 235.43 MH/s avg reported [diff -2.94%] (A247366:S1575:R0 shares, 93582 secs)

Look at that, a diff of -2.94% between the reported and accepted hashrate, what a coincidence? To be fair though, 247k shares is only good for a +-0.5% estimate at 99% confidence, so we must treat the value accordingly. The point is that neither CM nor PM can never ever produce a poolside hashrate over time that matches their displayed hashrates.

Sorry for a long rant to your simple question, the bigger point I'm trying to make is this: unless miners start accepting that CM and PM are bullshitting their displayed hashrates, "comparing" CM/PM/TRM/Ethminer is pointless, you'll just be stating that CM and PM are much better than what they really are.

dingdongtobias

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