using cast xmr only get around 800 h/s rx 580 8gb and 700 h/z for my rx 570 4 gb

[23:04:59] GPU3 | 87°C | Fan 1228 RPM | 634.8 H/s
[23:05:00] GPU1 | 63°C | Fan 1153 RPM | 690.6 H/s
[23:05:01] GPU0 | 72°C | Fan 1218 RPM | 686.2 H/s
[23:05:01] GPU2 | 81°C | Fan 1217 RPM | 737.5 H/s
[23:05:04] GPU4 | 67°C | Fan 1992 RPM | 633.2 H/s
[23:05:04] GPU3 | 86°C | Fan 1218 RPM | 634.2 H/s
[23:05:04] GPU1 | 64°C | Fan 1156 RPM | 689.3 H/s
[23:05:06] GPU0 | 72°C | Fan 1219 RPM | 687.4 H/s
[23:05:07] GPU2 | 79°C | Fan 1209 RPM | 734.9 H/s
[23:05:08] GPU3 | 88°C | Fan 1222 RPM | 634.6 H/s
[23:05:08] GPU4 | 67°C | Fan 1992 RPM | 633.8 H/s
[23:05:08] GPU1 | 65°C | Fan 1157 RPM | 689.3 H/s
[23:05:10] GPU0 | 72°C | Fan 1219 RPM | 687.8 H/s
[23:05:12] GPU2 | 80°C | Fan 1211 RPM | 736.3 H/s
[23:05:12] GPU1 | 63°C | Fan 1155 RPM | 689.8 H/s
[23:05:13] GPU3 | 87°C | Fan 1228 RPM | 634.4 H/s
[23:05:13] GPU4 | 71°C | Fan 1992 RPM | 634.2 H/s