Whats with the amount of rejected shares?
accept: 1837 | reject: 506 | hw error: 28
Could be from when I restarted the server a couple times yesterday. My reject rate was a bit higher than normal for the past 24h too (but not nearly as high as yours). Global reject rate *after* the restart is 1.1%
With all those HW errors it sounds like your system may be broken. You shouldn't have any of those at all.
Also, this. You've probably overclocked your card too much.