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Title: Hashing slowdown Post by: Bitcoiner on July 15, 2010, 04:05:40 PM I've noticed that after running Bitcoin for a while, the hashing seems to slow down by a significant amount.
For example: 310 khash/sec -> 250 -260 khash/sec 2450 khash/sec -> 2150 khash/sec Noticed on two seperate machines, in Windows and Ubuntu. Any idea why this could be happening? Has anyone else noticed this? Title: Re: Hashing slowdown Post by: Svick on July 15, 2010, 04:25:12 PM Isn't that just because the difficulty increased?
Title: Re: Hashing slowdown Post by: Strofcon on July 15, 2010, 04:29:17 PM I think an increased difficulty just means more hashes are (typically) required to create a block successfully. I don't think it should slow the actual hashing rate though... my guess would be that it's something on the client's host that is consuming extra cycles and depriving bitcoin of CPU time.
Title: Re: Hashing slowdown Post by: knightmb on July 15, 2010, 04:37:13 PM Heat related probably. Your CPU is idle most of the time, so it's running cool. When you break out the hash, the CPU is running full speed and generates more heat. As it generates more heat, it will start to slow down slightly unless you have some kind of crazy fan setup or liquid cooling.
That's my guess anyway. :) Title: Re: Hashing slowdown Post by: SmokeTooMuch on July 15, 2010, 04:46:25 PM I think an increased difficulty just means more hashes are (typically) required to create a block successfully. I don't think it should slow the actual hashing rate though... That is correct.And this As it generates more heat, it will start to slow down slightly unless you have some kind of crazy fan setup or liquid cooling. could also be correct. All newer CPU'S start throttling down their speed if they recognize a high temperature. It's a safety feature.So mabye that's your problem. Try reading you CPUs temperature sensor out (I recommend CoreTemp (http://www.alcpu.com/CoreTemp/)) and tell us what temperatures you have when the hashing slows down. Title: Re: Hashing slowdown Post by: Bitcoiner on July 15, 2010, 05:22:33 PM I think an increased difficulty just means more hashes are (typically) required to create a block successfully. I don't think it should slow the actual hashing rate though... That is correct.And this As it generates more heat, it will start to slow down slightly unless you have some kind of crazy fan setup or liquid cooling. could also be correct. All newer CPU'S start throttling down their speed if they recognize a high temperature. It's a safety feature.So mabye that's your problem. Try reading you CPUs temperature sensor out (I recommend CoreTemp (http://www.alcpu.com/CoreTemp/)) and tell us what temperatures you have when the hashing slows down. I should clarify that if I stop and start it 1 second later, the hashing goes back to fullspeed and stays there for a while, so I don't think that's the issue... Title: Re: Hashing slowdown Post by: Bitcoiner on July 15, 2010, 05:27:10 PM I think an increased difficulty just means more hashes are (typically) required to create a block successfully. I don't think it should slow the actual hashing rate though... That is correct.And this As it generates more heat, it will start to slow down slightly unless you have some kind of crazy fan setup or liquid cooling. could also be correct. All newer CPU'S start throttling down their speed if they recognize a high temperature. It's a safety feature.So mabye that's your problem. Try reading you CPUs temperature sensor out (I recommend CoreTemp (http://www.alcpu.com/CoreTemp/)) and tell us what temperatures you have when the hashing slows down. I should clarify that if I stop and start it 1 second later, the hashing goes back to fullspeed and stays there for a while, so I don't think that's the issue... The desktop goes up to 61C CPU max. Title: Re: Hashing slowdown Post by: SmokeTooMuch on July 15, 2010, 06:13:30 PM 61°C shouldn't be a problem, so maybe it's a software issue.
Can't help you with that, but I'm sure the devs will. Title: Re: Hashing slowdown Post by: Strofcon on July 15, 2010, 07:10:20 PM You can check your other running processes too, and see if something else is registering a noticeable amout of CPU usage. Either Task Manager for Windows or top / nmon for *nix should work just fine for the task. Any %CPU used that isn't attributed to bitcoin/bitcoind is going to slow your hashes, even if it's only taking 5% of a core's processing muscle away from bitcoin. :)
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