https://bitmain.zendesk.com/hc/en-us/articles/204875015-How-to-diagnose-S5-hashing-PCB
Then
https://bitmain.zendesk.com/hc/en-us/articles/203559969-My-S5-hashes-at-about-600GH-S
Can you post a status picture is it seeing both hashing modules on S5? And what PSU are you using (model and watts)?
Thanks for those, I'll rig em up again in the morning and post a picture, but it was seeing both boards and giving temp data etc.. I'm using the bitmain PSU. Firmware is good, but if I run any higher than 200 I see a decrease in hashing, temps don't suggest this is a heatsink / thermal compound issue, seeing about 40c and it's bloody hot ambient today