Here is Guru3D's power supply recommendation:
GeForce GTX 560
•On your average system the card requires you to have a 500 Watt power supply unit.
GeForce GTX 560 in 2-way SLI
•A second card requires you to add another ~175 Watts. You need a 700+ Watt power supply unit if you use it in a high-end system (800+ to a KiloWatt is recommended if you plan on any overclocking).
Link Removed due to 404 Error
and now ?
you think it is the psu i understand but why the "power supply" test from occt 4.2 works successfully, why there is a link with directx kernel?
would it be possible that this is the drivers of nvidia ?
bad graphics card? Club 3D is a good brand?
be quiet too?
and thank you for all your answers
yea i have underclock
and this Plantage de "nvlddmkm.sys" : la solution
This further backs up my theory of the PSU not being powerful enough. I'd try running with one card in and see if the blue screens disappear."If a previously troublesome video card becomes stable when underclocked then it means that you have a hardware problem rather than a software problem."
Troubleshoot your video card by underclocking
a nice site to go to if you want to just learn the terminology, to get more familiar with the language, without bad ad links