I kept the PSU inside a rack and once the PSU would get really warm , well more than warm would cause all start of problems up to screen freezing and nothing happening. Once I opened the rack and give the PSU good ventilation and now the PSU is almost cold all the time, it is running smoothly from a few days.
1x 750 in the rack and had 1x 1400W outside and could get all the air it needed Just had 1 and then 2x 390 on the 1400W but no joy for long.
So many F******* variables to work out.
I do regret getting into mining as i did invest gradually as it worked out great with 1 card, then added another, then another, PSU, etc and then things took a turn. Now can't get it stable with just 1.
Will try changing the intensity and if that doesn't work i will need to format the C: partition and do a clean install and go with Windows10 this time. It is my main machine so not looking forward to it as i need to copy, backup, move so many files because there will be no going back after that.