The reported hashrate on ethermine is working fine here. Why don't you share your realtime mining link so we can investigate.

---

gtx 1660 with memtweak (bios mod) ~35MHASH !

--kernel 0 / GPUMemoryTransferRateOffsetAllPerformanceLevels=1700

57m [2021-10-18 17:57:42.023] GPU0 1660S 0.00 H/W 34.98 MH/s 35.01 MH/s 18/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU1 1660S 0.00 H/W 35.14 MH/s 35.11 MH/s 29/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU2 1660S 0.00 H/W 35.18 MH/s 35.10 MH/s 22/0/1 (100.00%)
57m [2021-10-18 17:57:42.023] GPU3 1660S 0.00 H/W 35.10 MH/s 35.01 MH/s 22/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU4 1660S 0.00 H/W 33.33 MH/s 33.49 MH/s 24/0/1 (100.00%)
57m [2021-10-18 17:57:42.023] GPU5 1660S 0.00 H/W 33.43 MH/s 33.47 MH/s 21/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU6 1660S 0.00 H/W 35.02 MH/s 34.96 MH/s 26/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU7 1660S 0.00 H/W 34.83 MH/s 34.96 MH/s 32/0/1 (100.00%)
57m [2021-10-18 17:57:42.023] GPU8 1660S 0.00 H/W 35.03 MH/s 35.03 MH/s 20/0/1 (100.00%)
57m [2021-10-18 17:57:42.023] GPU9 1660S 0.00 H/W 35.03 MH/s 35.03 MH/s 24/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU10 1660S 0.00 H/W 35.09 MH/s 35.01 MH/s 32/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU11 1660S 0.00 H/W 34.94 MH/s 35.00 MH/s 29/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU12 1660S 0.00 H/W 32.47 MH/s 32.42 MH/s 25/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] GPU13 1660S 0.00 H/W 35.16 MH/s 35.09 MH/s 30/0/0 (100.00%)
57m [2021-10-18 17:57:42.023] 0.00 H/W 484.71 MH/s 484.68 MH/s 354/0/4 (100.00%)

--kernel 0 low power,cards with few shaders, low intensity
..
--kernel 7 higher power good on cards with many shaders, high intensity

If your rig has low tdp, low intensity, autotune will probobly select a lower number kernel.
The rtx 3060 and up works best on 5-7
The gtx 1070 has a new record speed on kernel #4

[moderator's note: consecutive posts merged]