Running a one Blade S9 vs. running a three blade S7?

[wmabern]

Good morning folks.
I'm still on my first cup of coffee, so I hope this isn't a very stupid question for the hardware pro's.

I am running two S7's now along with my S9's. I have another S9 with a new auto-tune controller but only one card in that S9 appears to be working correctly. I have spent hours trying to get another blade hashing in it (I thought I had two good blades). I have tried different freq's, different PSU's, different cables, etc. Nothing seems to get more than the one card running.

Now, my question is: Is it better to run the single S9 with only one working card than running an S7 with all cards working? Energy consumption-wise?

I don't feel bad about pushing the S7 to 725mHz. I would probably set the S9 to 600mHz during the first boot in the auto-tune controller.

I feel like I'm wasting hash with a good board sitting around gathering dust. Any thoughts are greatly appreciated!!

Thanks all! Have a great day! :-)

[sidehack]

That one-blade S9 is basically a 400W S7.

[wmabern]

That one-blade S9 is basically a 400W S7.

Thank you. I've been wondering about that for a few days and that makes perfect sense. Thank you for clarifying it for this "old" brain! 
Best wishes!

[ConnerM]

Back in the day we used to pull whole units and send them to BMW for repair, but now when we have a bad board we do a calculation based on a 4 week turn around time. Most of the time it's better to let a partially hashing board (which might be down a few ASIC's) to run until dead instead of pulling it for maint while it is still partially functional. When we do pull dead boards we only remove the ones that need to be fixed and leave the unit on the rack and let the good boards continue to hash. So yes, much better to let a 1 board S9 run than not. Try replacing the primary controller board first, and if that does not bring the dead boards back up, pull them and send only those board out to BMW for maint. You can replace the controller on an older beaglebone S9 (those have the black board as part of the controller unit) with a new autotune controller, you just have to remove the front plate because the Ethernet port will not line up. You can get spare controllers and hash board cables right from BitMain.

If you're loosing S9 boards on the reg, and it's not a temp issue,  check the quality of your main input power.

[wmabern]

Back in the day we used to pull whole units and send them to BMW for repair, but now when we have a bad board we do a calculation based on a 4 week turn around time. Most of the time it's better to let a partially hashing board (which might be down a few ASIC's) to run until dead instead of pulling it for maint while it is still partially functional. When we do pull dead boards we only remove the ones that need to be fixed and leave the unit on the rack and let the good boards continue to hash. So yes, much better to let a 1 board S9 run than not. Try replacing the primary controller board first, and if that does not bring the dead boards back up, pull them and send only those board out to BMW for maint. You can replace the controller on an older beaglebone S9 (those have the black board as part of the controller unit) with a new autotune controller, you just have to remove the front plate because the Ethernet port will not line up. You can get spare controllers and hash board cables right from BitMain.

If you're loosing S9 boards on the reg, and it's not a temp issue,  check the quality of your main input power.

Thanks for your detailed reply. I will answer back tomorrow afternoon. I'm getting ready for the dreaded 10 hour night shift at a server farm. I get off at 5:00 AM.
Best wishes!