I tested Catalyst 14.7beta on Windows 7 64bit:
    R9 280X@1100/1500 MHz: ~6000 cpm (with two threads per GPU and -a 0)

I tested Catalyst 14.6RC2 on Windows 7 64bit:
    R9 280X@1100/1500 MHz: 5700+ cpm with -a 0 (and -t 0,0)

could some one help me out why i get this error when i load up 6 gpu

5 gpu work great but 6th always crash

https://www.dropbox.com/s/2ennp3d6nmetiov/Photo%20Jun%2002%2C%208%2000%2034%20PM.jpg

That seems to be a driver error because the memory addresses are negative. But I'm wondering why the addresses are 32bit long. Do you use a 64bit Windows (I guess 8.1) and which Catalyst driver do you use?

As I mentioned many times, the "slowness" of R9 290(X) seems to be caused by the driver. Every kernel executes much faster than on a R9 280X, but the card (or the driver) is not able to overlap the execution of the kernels like it is the case with the 280X. On Windows the 3 kernels are completely processed sequentially, so the Linux version is faster because at least one kernel is able to overlap with another kernel. Perhaps a different set of kernels which only need less than 1GB memory will circumvent this behaviour, but I can't give any guarantees because the R9 290(X) has different ACEs than the 280X, too.

Ok, I will test it this evening.

Linux or Windows? Perhaps you executed the wrong binary (32bit vs. 64bit) or you used the *Catalyst14 files together with Catalyst 13.x. Please post your command line options, your OS version, the Catalyst version and the output of clpts.

Everything is fine with v1.1a_linux.

Once there went something with the Catalyst wrong it is very difficult to repair the damage (on Linux).  I guess that the best thing is to try a fresh Ubuntu installation.