3 5830s, mixed results at stock.
#1 - had to use RBE to flash and increase to 1000 core, 300 mem, stable, 320 mhash
#2 - didn't have to use RBE, stable at 995 core, 300 mem, 318+ mhash
#2 - didn't have to use RBE< stable at 980 core, 300 mem, 310 mhash
#1 runs a lot cooler 62.5C, well ventilated case
#2/#3 run around 72-75C, which may be why they can't go as high
I have a couple of 6790s that run around 75-80C, no issues at 1000 core, 300 mem, looks like the 5830s are a little more temperature sensitive?
All of the above using phatk with +3% efficiency mod