Edit: To clarify, I am running Ubuntu 12.04 32 bit.
You have wrong kernel from sources (x13mod.cl = 31 KB), working kernel for 5850 and binary for windows is in my link (x13mod.cl = 281 KB).
Deleted old *.bin files, recompiled with the larger x13mod kernel, and it's giving me "Error -46: Creating Kernel from program. (clCreateKernel #name)" followed by a segmentation fault.
@t0mpr1c3 - read that :
example cmd line for 5850
sgminer -k x13mod -o stratum+tcp://boost.suprnova.cc:3311 --auto-fan -w 256 -g 1 -I 18 --thread-concurrency 7200 --lookup-gap 2
Works with Cat 13.12, works with 14.4 too. tested on 5850, 6970 and 5750
x13mod.cl - 281KB
https://dl.dropboxusercontent.com/u/88276654/x13mod.7z
Sorry but can't remember how I found it, was posted somewhere in a forum - with complete sgminer build, made 28-05 early in the morning Cheesy
PS: https://dl.dropboxusercontent.com/u/88276654/sgminerx11.zip thats the file I downloaded, the x13mod kernel inside is NOT compatible with later sgminer builds, so ...