Etherum with R9 390 (31MH/s) and 7970 Lighting at 25MH/s, solid enough.
That is very fast for the 7970 at 25 MHz/s. Does it have modified BIOS to reduce the memory timing? Usually it is just 23-24MH/s.
No. Clocked to 1150/1600 (Lighting)
setx GPU_FORCE_64BIT_PTR 0
setx GPU_MAX_HEAP_SIZE 100
setx GPU_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
ethminer.exe --farm-recheck 200 -F http://192.168.1.15:8080/eth1 -G --cl-local-work 256 --cl-global-work 8192