Zcash hashrate drops


I am using EWBF’s CUDA Zcash miner Version 0.3.4b to mine ZCASH. When I open the miner my first hashrate is good: ~ 2550 sols, but after 30 sec the hashrate drops drastically to ~2200 sols

This is my batch file:

miner.exe --server eu1-zcash.flypool.org --user “mywallet”.Miner01 --pass x --port 3333 --cuda_devices 0 1 2 3 4 5

6 x MSI AERO GTX 1070, AsRock H81, Corsair AX1200i.

MSI Afterburner settings: 70 power limit, 150 core clock, 600 memory clock, 75% fan speed.

Does anyone know which would be the problem?


Try it again without any OC

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This is relatively normal per my observations. Is your card hitting any sort of “throttles” at all after about 30 seconds? Temperature limits? Max power consumption limits? Generally there seems to be a “warm-up” cycle or two when you first turn it on that it is notably higher than normal performance but then it levels off shortly after.
Can’t speak to the exact reason why but it was much more noticeable in my rigs when I was having temperature and airflow control issues.


Force your fan speed to 95% and see if it’s better.

Also add flags --pec --fee 0.1

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I think I remember seeing somewhere that lowering the dev fee from the default setting results in lower sol/s or shares received? Was that just b.s.? Are there no disadvantages from lowering the dev fee aside from not contributing as much to the dev fee?

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based on your setup and oc setting, i think you should be getting 430 - 460 sols per card, which translate roughly 2500 - 2700 sols…

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My temp limit is 70C at these settings.It starts with 2600-2700 sols and after 30 secs drops ar ~2200, 2300, 2400.

Done. It keeps constantly ar ~2550. Much better. But I have a questions? My GPUs are safe with fan speed at 95%?

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But I don’t get with these settings

Safe? yes of course. Your fans will wear out faster though. But…calculate the cost of fan replacement versus hashrate and longevity increase of the rest of the card. replacing fans comes out better for my own calc.
You could keep turning fan speed down till you see temp rise above your comfort level, then add 5%

Kahooli, thank you for your answer. I will try and keep you updated.

Enjoy your day!

For 90% fan speed I can get 2650 sols. I think is pretty good. :slight_smile:

i heard that lowering the dev fee can cause the hashrates to slow down even if it doesnt appear that way in the console…
is this not true?

I figured the immediate drop off of hashrate after starting was due to heat. I see the temperature increase dramatically after starting and the hashrate drop at the same time. Once the temp stabilizes so does the hashrate.

i dont think thats true, but why not contribute to the devs who work hard so you dont have to?

EWBF wasn’t greedy. The feature is there on purpose.I left it on long enough to generate a significant sum for them. Even .1% synthetic equity in the equihash space is huge.

I be worried about fan failure. Getting a replace from the maker of the card can be very hard to do. I know I lost fans before and now a days I never run my fan more the 60%. I use a cheap box fan and mount it on top of rig. I set it to low and sometimes medium if its hotter out side.