I am trying to run 4 x Zeus blizzards on the one Raspberry Pi, and it doesn't seem to be coping. I am using bfgminer 4.4.0 and even at a lower clock of 308 I am getting like 20% HW errors and all sort of problems, like sometimes not all of the blizzard will start and I have to quit bfgminer and launch it again, I often get ZUS 0: Comms error (werr=1) and other bad looking messages. The CPU load is about 1.5.
Anyone know the practical maximum of Blizzards you can run of a single Pi?
May I ask you are using 308 and not stock 328? or even 240MHz
As for the HW errors.
Documentation as well as user experimentation has shown that Zeus hardware prefers higher difficulties as compared to Gridseed.
Using difficulty values of 1024 or 2048 are not unheard of for use on a single Fury/Blizzard and offer good results. Link to thread that has a growing list of pools which support the manual setting of difficulty:
https://bitcointalk.org/index.php?topic=645532.0 (Thanks jekv2!)