What kind of power supplies are you using?
3 IBM 2880 PSU with Jabberwock mods
The batch 7 uses: 1278 W (at the wall, with APW3, 93% efficiency, 25C ambient temp)
The batch 8 uses: 1293W + 10% (at the wall, with APW3, 93% efficiency, 25C ambient temp)
I'm pretty sure the batch 7 numbers are off, but with these numbers we're at 2571W per PSU for a platinum rated PSU.
I've been running these miners since the middle of december with no problem... until now.
The batch 8 uses: 1422W, 1293 + 129 (10%). Our results are a little higher than this.
Total watts used: 2700, if the numbers posted by Bitmain are correct.
Updating the firmware is always a good idea, read the change logs and see what others have experienced first. But will the B7's work on their own not alongside the B8's?