Some update here:
1060core/1800mem ~750kh/s (If I set the core @65 the card drops to ~650kh/s)
1075/1820 ~760kh/s
@MTJ151 We need to find a modded BIOS with tighter VRAM timings.Search for "Stilt BIOS"
The hardware of the cards is capable of +800kh/s but not with these timings.

Hi everyone. First time poster here and I would like to share some info and ask for advice. I bought 4 280x TOXICs a week ago with  015.043 BIOS.Here is my setup and results:
WIN 8.1 64-bit Catalyst 13.12 + 2.9 SDK
cgminer 3.7.4 and sgminer 4.1.0 config:
"intensity" : "13",
"worksize" : "256",
"lookup-gap" : "2",
"thread-concurrency" : "8193", (8192 for some kernels)
"gpu-threads" : "2",

On 1050core/1500mem clock I get 736-740kh/s with all of the new kernels in the sgminer dir.
On 1080/1500 600-650kh/s.
On 1060/1800 ~750kh/s.
On 1150/1800 ~550kh/s.
MTJ151 can you tell what is the difference between our two setups?
I understand now that is will most likely not be possible to get 800+kh/s form these cards so my goal now is to find a stable 750-760kh/s. with decent power consumption and temps.