Well, i'm no expert, only have 5800 and 5900 series cards, but gpu-memclock seems high.
Does the 7850 need such high gpu-memclock?
Seems that people clock the memory to 800/900 for that card.
https://en.bitcoin.it/wiki/Mining_hardware_comparison#Popular_Mining_Cards (scroll or search page for 7850)
maybe give that a go.
With mine it was a case of trial and error untill I found GPU memory and voltage settings that were stable.