Hi guyz...!! I have purchased 3 x sapphire dual x OC edition R9 280x Graphics cards and to minimize the cost, I purchased 4 PSU ...1 for mobo, and 3 for graphics cards. For now I am testing with the 2 graphics cards and 3 PSU. The Graphics card is 8 + 6 pins pcie graphics card in which 1 is connected to pci-e x16 2.0 slot and 1 is fitted on 4x slot. Both the Cards are connected with individual power supply of 550W corsair PSU which has efficiency of 85%, a verified PSU with 42A output and 2x pcie cables of 6+2pins delivered 508W according to rated power on single +12v rail. Now these Graphics cards with separate PSU are powered ON from the main supply that is connected to the motherboard. I have fitted a spare power supply of 450W/34A single rail to the motherboard and using 550w on gc as discussed above. Please check the images below:
http://imageshack.com/a/img801/8572/q73v.jpg
http://imageshack.com/a/img856/8598/7kxj.jpg
http://imageshack.com/a/img856/4715/xwx2.jpg
http://imageshack.com/a/img811/4371/ydtc.jpg
I have build this rig for mining purpose and the problem is that :-
1. The PSU turned off automatically after few mins. and actually do not heat up because 550W is sufficient to deliver power one gc and i.e. Dual X on 1050 engine clock.
2. The cards on individual power supply are turned off due to cut off and shut down the 550w PSU. Mobo power remain ON with 450W supply, do not interrupt the mobo power but graphic cards remains off. After mining for half hour or 2 ..or at some random time, the gc turned off due to power shut from the 550w supplies. The 550W psu turned OFF completely and there's no fan running inside the supply chasis.
3. I have tried changing the BIOS, unlocked voltages and running at min. 1.100v stable ranging 1.100-1.200v. I have also tried changing the PSUs and all in vain. I have also changed the platform from Intel to AMD all in vain.... All psu are checked and tested with motherboard and different OS like LINUX Ubuntu x64, Windows 8 x64 and Windows 7 x64. No problem with motherboard and PSU. Latest AMD SDK and Catalyst 13.12 stable installed.
4. If I run only 1 graphics with the supply that is connected to motherboard, it runs fine. But it doesn't work with individual power supply when Green and Black wire is short circuited to power ON the psu. Having a problem with spare connected power supplies...
WHAT should I do??
I am trying all these from last 1 month and do not able to debug the problem. PLEASE HELP!!!! I have invested $2000 on this small rig.