mining 5 Gigabyte 280x and one mother board (wattage and multiple PSUs)

[joneustace]

Hey guys, just jumping into the mining scene. I have purchased 5 Gigabyte 280x cards and I plan on using them on the H81 pro btc mobo. My question is a wattage one.

I have just bought 5 powered 1x to 16x riser cables, I plan on connecting the gpus directly to the PSU(s), but it seems that even the best PSU I can find (1600w) only has 4 12v 30amp rails, and 2 12v 20amp rails. I don't think the 20amp rails support enough amps for the cards while mining.

So, my question is, is it safe to connect one of the graphics cards directly to a second PSU without splicing them together? Can I fry any of my hardware doing so?

I've seen adapters that allows you to connect two PSUs but I don't know if this is a good idea.

 

[JuX]

Actually I think that those r9 280x need 42 amps on he 12v rail..
And it's not a good idea to use 2 PSU's for one system, bad things can happen I've heard.

 

[unksol]

the TDP of the 280X is 250W. it needs 21A not 42A.

it will probably run them but multi rail supplies should be avoided in general and then you won't have to worry about it.

 

[joneustace]

the TDP of the 280X is 250W. it needs 21A not 42A.

it will probably run them but multi rail supplies should be avoided in general and then you won't have to worry about it.

Is it possible to combine the 2 20a rails?