just tested 3 cards separatly and they all mine perfect. When i want to run 2 cards together it crashes after some time ... so would this be something with PSU or with MOBO? its defenatly hardware related. i know i could easily fix it with buying a 6 pci motherboard ( asrock h81 pro btc ) and with a PSU of 1200 watts but i try to mine with hardware that i have available for free here at my home. so again , setup is 3 cards on 1 mobo and each card has its own 300 W PSU and the mobo has its own 300 w PSU. pci riser of each card is connected to the PSU from that card ...
please help
What cards are you trying to use?
A 300W PSU is no good for mining and you said you are daisy chaining like 4 PSU?
Why would you do that? Add2Psu is like £20 each and you have 4! Or are you doing some of your own wiring hacks?
I would say undoubtedly a power issue, however, you didn't say what mobo.