How many people have upgraded the S4 firmware to: initramfs.bin.SD-20141016.tar.gz from the bitmain website?
I only ask because mine is still running on the factory firmware no problem with difficulty manually set, so I'm kind of wondering if I should bother with the upgrade.
I upgraded all of my S4's to this firmware and gained at least 5% hashing speed on the pool. I also set difficulty to 2048. 225 Mhz 0725 volts . They are all hashing at least 2200 and are stable meaning I don't have to hard reboot them every day for crashed chips or reduced hashing speeds.
Maybe I need to upgrade my firmware. When S4 hashing rate drop to below 1500 Gh/s, my pool with Ghash.IO goes to zero. I had difficulty set to 2048 manually.
Looks like your hashrate dropped to
0 over 14 hours ago. It just took that long for your average to get below 1500. I upgraded all of my S4's to the latest firmware (Oct 16) and have not had any issues, except I needed to reboot another time after the firmware upgrade, on all of them. All of them ran poorly after the automatic reboot from the firmware upgrade. But I always set the difficulty manually when the option is offered by the pool.
Do you know how high the board temps are getting? The UI shows 50-51 now, but it hasn't been hashing. I've seen this (hashrate drop to 0) happen with temps in the 60's. They should be able to handle 60, but I'm just passing along what I have seen. I have also seen this happen when trying to overclock with stock PSU. (I can see in your screenshot that you are not overclocking, but wanted to mention it anyway.)
You should setup some kind of alerting. You don't want to lose half a days worth of mining on an S4. There are a couple home grown monitoring programs out there. They require a bit of work to set them up. I see that Justin Ramos shares open-source monitoring software. I don't know him. I have tried his P2Pool code, which is good and has extra reporting. I intend to try his monitoring solution. I think you have to install 3 software packages. The API client, the manager, and the monitor.
https://github.com/jramosI also ran across this site, if you want fast and easy.
http://www.awesomeminer.com/ There is a one time charge for the version that send notifications. There is a free version to try. I don't know this site and am not endorsing them, but their product looks good. If you search for "bitcoin mining monitoring", you will find others.