I am losing hashrate on R9 390, I used to mine at 31MHs at 1140/1250 under linux, now I just get 26.8MHs, is this normal due the DAG file size? or kernels tweaks decrease the hashrate of the R9 390? I tried with -oldkernels and -asm 0 but nothing, under windows I can get 30.5MHs, any thoughts?

Thanks