Honestly for me every miner is a little different. With the exception of the 2 batch 7's the firmware is on those factory installed and on one of them I left it at 625 MHz and it mined at the advertised 5TH, the second batch 7 at 625 was performing poorly and I was only getting around 3.8TH so I dropped the freq to 600 and then is jumped up to 5TH. The 19 others I have are batch 2 (which were advertised to run at 4.66TH at 575 TH), I flashed them with the most recent Bitmain firmware that supports the 600Mhz setting. When I had the time I found that really going through them slowly and taking my time tweaking with the frequency (and not always up) making small changes has made an incredible difference. For instance, I have some of mine set at 606MHz and some set 593Mhz. I do not think I have anything set over 625 but you can certainly try. Just make sure you are monitoring it closely when you make changes like that. I guess the whole point I am getting at is there is not perfect setting for every single miner out there. You can have rough guidelines that work for most but if you are trying to dial in your farm, then you need to play with the settings to see what works with your farm. Also keep in mind not all miners are going to perform at the highest Th rating possible. Some of my miners no matter what settings I have changed and close I think I have dialed it in, I have had to settle for 4.5Th when I should be getting 4.8 and that ok, its just the way it goes. If you are interested you can check out my mining set up here
https://www.youtube.com/watch?v=K1C2LQnBr2Y
If you like it, subscribe as I am always adding new content and I love audience feedback. I look at bitcoin as a group learning effort. In fact your thread has kinda of inspired me to create some kind of video addressing this very issue because I have seen this question or variations to this question come up before where people have had performance issues when dealing with several of the same type of bitmain products. They are frustrated why two or more of the exact same product do not operate the exact same way.
I hope this help!
https://www.youtube.com/watch?v=K1C2LQnBr2Y
If you like it, subscribe as I am always adding new content and I love audience feedback. I look at bitcoin as a group learning effort. In fact your thread has kinda of inspired me to create some kind of video addressing this very issue because I have seen this question or variations to this question come up before where people have had performance issues when dealing with several of the same type of bitmain products. They are frustrated why two or more of the exact same product do not operate the exact same way.
I hope this help!
This has been my experience as well! I have some running at 631 without a hitch, and some won't go above 600 before the hashrate PLUMMETS and hardware is up in the 0.x% range. Most are good around 625 frequency, but I've had to fine tune each one to optimize it, and it doesn't appear to be heat or PSU related, it's completely luck of the draw. Hardware error seems to be a good indication, if they are very low (0.00xx%) you can try bumping frequency up one step at a time, and letting it normalize for a couple hours to see if it nets you better hashrate and minimal increases in HWE. I have 2x B1's & 5x B5's, and there's no rhyme or reason as to why some will only do 600 and some are up to 631 and 5+ TH/s (maximum I'm comfortable with for my environment).
Lucky for me, the lowest one out of my units does 4.8 @ 600 frequency, and best one does 5.09 @ 631, most of them do around 5TH @ 625 frequency.
this unit with a evga 1600 t2 does freq 600 with 0%
my best one by far. and if I use the meanwell at 12.4 volts I can do much higher
