2 kerney66

Now got my hands on radeon 7 (power color with samsung mem).
1540/940@850mv + some timings (similar with my vega64) + 13*13 mode and I have 2.77khs.
Is it ok or should I expect higher results with some tuning? I am not considering to increase voltage and gpu clock. Don't want extra heat.
So, is there a way to get boost without increasing gpu clock?