mining with 650 psu

[ayayay]

I have a r9 290 card what other card can I add safely

[avidwriter]

7850 maybe? 

[zmhaha]

the 290 takes about 300w
add another 150w for the rest of the stuff, totaling at 450w

so for the extra 200w left on the psu, I would not bother to add anything.
Usually 50%-60% load is the sweet point for efficiency.
And currently any GPU uses about 200w while mining is not worth it in terms of Kh/s vs electricity

[ayayay]

so if I add a  Platinum 850W+ ATX12V / EPS12V 80 PLUS PLATINUM Certified psu can I then run 2x r9 290's

[defosp]

so if I add a  Platinum 850W+ ATX12V / EPS12V 80 PLUS PLATINUM Certified psu can I then run 2x r9 290's

+

[zmhaha]

so if I add a  Platinum 850W+ ATX12V / EPS12V 80 PLUS PLATINUM Certified psu can I then run 2x r9 290's

For a 850w, you can certainly do 2x 290. but make sure you get a good one like corsair or seasonic. It is easy to put the numbers on there but the actual performance is way below.

Also, 2x 290 will take 600w at least, and adding another 150w for the rest of the stuff. you are looking at 88% load for 24x7.
efficiency wise, neither good or bad for a platinum(but again, make sure it is indeed works like a platinum).
But, PSU will age and much quicker when you constantly put high load on it. When this happens, the rated 850w will becomes lower.
Usually after a year of heavy uses, you can expect about 15% loss of that rated power.
So I would get a 1000w gold for 2x 290 and the system.

[grimrog]

i run 2 280x at 740kh each on 680w 80+ bronze from be quiet!. There is room for improvement, i didnt undervolt the cards at all.


The rest is a typical self built pc stuff, 2 HDD's+1SSD, Phenom2 X3 720, Asrock G780gxh, 6gb DDR2 Ram. The third card is already here and the 1300W EVGA psu i ordered a while ago will take just another few days.