Hello everyone. My 280x are giving me only 2.15 mh/s. My settings are :

{
"pools" : [
   {
      "url" : "stratum+tcp://limi.maxminers.net:5555",
      "user" : "xxxxx.3",
      "pass" : "x"
   }
]
,
"intensity" : "18",
"vector" : "1",
"worksize" : "64",
"kernel" : "bitblock",
"thread-concurrency" : "8192",
"lookup-gap" : "2",
"gpu-threads" : "2",
"gpu-platform" : "0",
"kernel-path" : "/usr/local/bin"
}

Also i would like to add that i have four cards  and only 4gb of ram so maybe that is a problem? I see everyone is getting about 2.7 mh/s or 2.8 mh/s Does anyone have any idea what could i do to get that performance?

{
"pools" : [
   {
      "url" : "stratum+tcp://limi.maxminers.net:5555",
      "user" : "xxxxx.3",
      "pass" : "x"
   }
],

"name" : "x15",
"algorithm" : "bitblock",
"intensity" : "20",
"hamsi-expand-big" : "1",
"gpu-threads" : "2",
"worksize": "128",
"temp-cutoff" : "95",
"temp-overheat" : "90",
"thread-concurrency" : "8192",
"shaders" : "2048",
"api-listen" : true,
"api-allow" : "W:127.0.0.1"
}