My Hashrate drops from 270.000 Sols, to 40.000 Sols?

[jinsu]

Reducing the intensity could solve the problem.
Take a look into this thread, especially this post:

How to fix "GPU #0 returned incorrect data!" R9 280X?

had that issue also with some R9 280x vapor-x cards, latest claymore is really pushing the cards. When you see errors, try setting : -i 8 -cclock 1080 -mclock 1500 -tt 75 The sols are almost the same, and the cards that had these issues look stable Only had 2 cards from the 16 that had these issues.