Mining Rig problem, need help!

[wedge]

I've got two identical rigs.  Here's the specs on both:

AMD Athlon II dual core
Kingston 4GB ram
MSI 990FXA-GD80
4x Gigabyte GV-R795WF3-3GD
Powered 20cm pci-e risers from hashratestore.com
Seasonic X-1050

They are running BAMT 0.5C off an 8GB usb stick.


One of them is working perfectly, running 24/7 for almost two weeks with no issues.
The other one works perfectly, if I only install 3 cards.  If I install all 4 cards, they get detected, and they work for a short time.  But within the first hour, I will find that machine shut down.  The power button on the motherboard is unresponsive, I have to switch it off and on at the power supply to bring it back up.

It can't be a power supply issue, because both machines are identical, it would affect both.  1050W is plenty for 4 cards anyway.  I got an RMA for the original supply on that rig, but the replacement is doing the same thing.  I've even switched the p/s from the bad rig to the good rig.  But still the same problem on the same rig.

It's not one of the cards, or any of the pcie slots, or the risers.  As I've tried them all independently, and even switched some of the cards from the working machine to the bad one.  But it still shuts off whenever any 4 cards are installed.


I suppose it could be a motherboard issue.  But why would it only happen with 4 cards?  If it was the motherboard, I would expect it to happen with any number of cards.  Since the cards have their own power source, and I'm using powered risers.  The motherboard shouldn't feel any difference from the number of cards in use.

It really seems like a power issue to me, but it can't be the power supply itself...


This has been going on for 2 weeks now, and I can't figure it out.  Any help?



Actually, while typing this, I may have figured it out.  It could be the electrical circuit that rig is on.  This is an old house, and some of the wiring/breakers might not be so good anymore. 
The good rig is plugged into a new circuit with new wiring that I ran myself.  The bad rig is plugged into one of the old circuits in the house... The power might be dirty on that circuit, or it might have more voltage drop at higher load.
 I'll try switching it to a different outlet and see what happens.

[Zanatos666]

You might also try a UPS to help regulate that power as well.  If it is a power issue this could solve that problem for you.