I've got both a 7870 and a 7870XT running on 2 different linux systems.
with cgminer (2.11.4) (diablo kernel) or poclbm I get ~420 MH/s @ 1100core/950 mem on the 7870. CGMiner settings are worksize 128 and intensity 12 with 2 threads. Cat 13.1 and SDK 2.8 on ubuntu 12.04 32bit.
with poclbm I get ~500MH/s @ 1100core/950mem on the 7870XT. Poclbm settings are -w128 -f10 (cgminer seemed to crash a lot more than poclbm on the system I have it in). Cat 12.11 and SDK 2.8 on ubuntu 12.10 64 bit.
I found a drop in hashrate when using the 13.3 beta drivers, although I've not tried the 13.4 driver. I also found that the phatk kernel performed worse on both.
Hope that helps
with cgminer (2.11.4) (diablo kernel) or poclbm I get ~420 MH/s @ 1100core/950 mem on the 7870. CGMiner settings are worksize 128 and intensity 12 with 2 threads. Cat 13.1 and SDK 2.8 on ubuntu 12.04 32bit.
with poclbm I get ~500MH/s @ 1100core/950mem on the 7870XT. Poclbm settings are -w128 -f10 (cgminer seemed to crash a lot more than poclbm on the system I have it in). Cat 12.11 and SDK 2.8 on ubuntu 12.10 64 bit.
I found a drop in hashrate when using the 13.3 beta drivers, although I've not tried the 13.4 driver. I also found that the phatk kernel performed worse on both.
Hope that helps