I suggest you get a kill a watt meter under 30 bucks.
I suggest you do not over clock.
I have a 1000 watt fractal design I run 2 ants it is a platinum it pulls 718 watts at the kill a watt plug.
You can be certain It would be at 880-920 watts if I oc it.
and my psu would get hot and shut down.
A 1000 watt psu does not like to put out 900 watts 24/7/365
A kill a watt meter is a must for you
http://www.amazon.com/gp/offer-listing/B00009MDBU/ref=sr_1_1_olp?ie=UTF8&qid=1392368012&sr=8-1&keywords=kill+a+watt&condition=new
also you could try gravito's idea and plug in a 2.5 inch hdd to a sata jack. the pc may not like an un balanced load .
you are still getting close to redline . if you have a kill a watt meter and the 2 units pull 800 watts with 1 oc and 1 normal I would think the psu does not like an unbalanced load ie all 12 volt.
for now try no oc since it is free and safe. tell us if that works
Thanks all for your suggestions and help.
The X1050 has 3 PCI-E slots. Based on the load-balancing idea, I tested 1 at each end, leaving the centre empty, both ants running OK. I thought it could be middle PCI-E slot faulty so sent the PSU for an exchange. New PSU same problem. Now running ok for 30 mins. Pray that it lasts.
Both OCed to 190G.
Thanks again.