del

[myself]

del

[1714056816]

1714056816

[1714056816]

1714056816

[1714056816]

1714056816

[1714056816]

1714056816

[1714056816]

1714056816

[geckogroove]

driver issue or dead card, sorry... that's my opinion anyway, might not be accurate

[deslok]

It operates normally till you start mining? Is it overclocked at all?

[deslok]

Try downloading a new copy of gui miner. Also if you're using poclbm try phoenix or vise versa

[deslok]

How large is your psu?

[deslok]

720 watts should be fine for 2 cards but will likely be insufficient for three. You don't mention how many cards you have in the miner.
That being said if it worked fine until today you could verify the psu by switching out between miners.

[cicada]

the problem is that these PSu dont have 80+ certificate 
i took one off(need to get a tester i think is dead) and put another that is certified (700w) now mining whit 5x5850

The 80+ certification means that the PSU is at least 80% efficient over all loads - in other words, to get 100W out it may pull 120W at the wall.  Generally these PSUs are more than 80% efficient, with the highest efficiency between 50-70% of their maximum load.  80+ Gold PSUs are often 89%+ efficient at those loads for example.

Your non-80+ PSU should still deliver the quoted maximum wattage, but may be pulling significantly more at the wall.  If it's rated 750W, it should deliver 750W without a problem.  Of course maxing it out is definitely not good for a cheap/generic PSU, it will eventually burn out on you.

If that 700W 80+ PSU is running all 5 of those 5850's, you're really close to max, if not exceeding it, which is bad for efficiency and probably worse for the PSU.