4 cards all with 1x risers - system shutdown, please help!

[barabashko]

Im trying to mine LTC.
Mobo is MSI FM2-A85XA-G43 and 4 video cards are 280x.
PSU is 1200wt (galaxy hof 1200)
Risers i have are all 1x-16x, trader told me that there is no any difference to use 16x or 1x for mining, but 1x is better for ventilation.
I did't know that i can connect 1x to 16x slot on mobo which is true

BUT, when i start mining system is shuting down (using BAMT 1.5 and cgminer).

I have Sapphire Toxic, wich is working great and have 1256 by default.
With 3 cards its working fine.

It is problem with 1x risers? I need power risers? They are to expensive due great deficit and 1.5 month of waiting.

[1715021809]

1715021809

[barabashko]

i tryed to use 3 of 1X slot + 1of 16x slot
and and 2 of 2x slot + 2 of 16x slot

still its shuting down

what should i do? seems like person of the year is not going to help in my situation ( https://images.weserv.nl/?url=i.imgur.com/gwVOD.jpg&fnr ) ?

[barabashko]

seems like problem is in toxic, due http://www.anandtech.com/show/7406/the-sapphire-r9-280x-toxic-review/4
it can eat u pto 450wt  my god...

[zedicus]

i got a couple unopened toxics here..

you try undervolting? What are you getting at the wall?

[barabashko]

I solved the problem - add 1 more PSU!
1200wt is not enough for 4xToxic at default configuration. Yes you can undervolt, but i want IT ALL! since OC is very good show for kh/s

[zedicus]

^^ Dam those toxics suck down some juice eh! Im not looking forward to setting those up.. I was hoping to do 3 on a 1000w EVGA powersupply 4 would be sweetness!!!! I just saw a rig with a 1000w LEPA running 4 280x's!! I saw them in the show your mining rigs section of bitcointalk!

I even asked him, if he was undervolting and he said yes and with no problems... Clearly he didnt have the toxic editions!

[barabashko]

even my 4 x asus 280x dc edition dont run smoothly with 1.1v and 1000 core
with enermax 1250w revolution
so i aded 550wt hiper yesterday and it runs without any crashes now