What hashrate of your card ?
My MSI r9 280x has got 19.2->19.6Mhash/s as 7950, driver 15.12 core 1030 -mem clock 1250
If you asked me, then under Linux
ETH - Total Speed: 61.890 Mh/s, Total Shares: 3663, Rejected: 0, Time: 33:30
ETH: GPU0 19.493 Mh/s, GPU1 21.205 Mh/s, GPU2 21.192 Mh/s
DCR - Total Speed: 1237.804 Mh/s, Total Shares: 5537, Rejected: 66
DCR: GPU0 389.854 Mh/s, GPU1 424.104 Mh/s, GPU2 423.846 Mh/s
GPU0 - HD7950 @ 1050/1550, -dcri 40 (ASUS, somehow lesser than @Windows where similar card gives 20MH/s)
GPU1 - HD7970 @ 1150/1500, -dcri 40 (MSI Lightning BE)
GPU2 - HD7970 @ 1150/1500, -dcri 40 (MSI Lightning BE)