Three of my four B5 S3's are all steady at 477+ Gh/s with freq 237.5 with the fourth never seeming to go over 460, did find one x on that one but that's after a week of 237.5 so I just reset it without worry.
Anyway, as for what I finally did. I put one of the three "good" S3's on freq 250 and were now 15 mins in with no X's and ~500Gh/s.
If it runs well or at least an hr I will try 250 on the other two "good" ones doing ~477Gh/s
In philipma case he had one running 24hr OK on 250, then had to be restarted and was NEVER able to run at 237.5 again. For me it means that you will be better off keeping most miners either on 237.5 or 243.75 instead of swinging for 250 or 256.25
that was batch 4. they are both stable at 231.25
the batch 6 did all the way up to 256.25
but really bad hw
they like 237.5
these s-3 units are picky.
they even get different numbers pool to pool
i suspect it may be how far you are from the pool's server's.
I am getting this psu on fri will see if it runs 4 s-3's
http://www.amazon.com/gp/product/B00MMLUIE8/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
i know it is far more $ then the 1300 watt model but it will be fun to test.
at morebloodwine :
#option 'freq_value' '0982' #250M
#option 'chip_freq' '250'
#option 'timeout' '16'
option 'freq_value' '1306' #243.75M
option 'chip_freq' '243.75'
option 'timeout' '16'
#option 'freq_value' '1286' #237.5M
#option 'chip_freq' '237.5'
#option 'timeout' '17'
#option 'freq_value' '1206' #231.25M
#option 'chip_freq' '231.25'
#option 'timeout' '17'
#option 'freq_value' '0882' #225M
#option 'chip_freq' '225'
#option 'timeout' '18'
#option 'freq_value' '1106' #218.75M
#option 'chip_freq' '218.75'
#option 'timeout' '18'