Graphic Cards Crossfire cards within the limits of 5 ampere wall power

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Fifth_ID

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Hello,

I think that most power outlets in India are rated at 5A.

Is it possible to run a 2 x 7970 system on a 5 A wall outlet?

I plan to use it for litecoin mining so I'm probably going to chose a low cost processor and low cost crossfire motherboard.

My current setup is an i3 2100, 4gb , 32 bit windows and I'm planning to start litecoin mining by purchasing a HIS 7850 ICEQ and 520 Watt seasonic psu. In case I'm comfortable with my returns, I plan to go for a 7970 x 2 mining rig, 7970 + 7850 mining rig or 2 x 7850 mining rig depending on what's the most an Indian wall power outlet of 5 A can take.
 
I thought a high-end PC could run off a 5A socket? You are going to need a better power supply (something in the order of 850~1000W for a better efficiency) which is understood but I believe it can be plugged to a 5A socket. There are a few home appliances with similar power ratings that can work safely on a 5A socket.
 
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I read that 5Amps on a 220 volt line provides 1100 Watts and I've read online that some with 7970s use nearly 600 Watts so I thought I'd double check to see if any one on here is running a dual 7970 set up on an ordinary wall outlet. A dual 7850 set up should work without issue.

I'll get a new psu for the pure litecoin mining rig. 7850's shouldn't exceed 350 watts each. Seasonic 850Watt for 7850s x2 or Seasonic 1250 Watts for 7970 x2[DOUBLEPOST=1365060123][/DOUBLEPOST]7950's should work fine with a 1050 Watt PSU. The 7970's using excessive energy seems to be the exception than the norm and probably would work with a 1050 Watt PSU too.

One other bottleneck I'm thinking about are UPS's. APC UPS's have a 1000VA rating and then jump straight to 1,500 VA. Since the monitor won't be active, a 1000VA UPS should be sufficient?
 
I used to run a 4870x2 off a 5a wall socket and it melted the switches in three months. I then got a 15A unswitched socket bult for my APC 1500 UPS (which used a hacked adaptr earlier) and it has worked fine since. 2X6970 and a 3008wfp, peak power is around 650 watts.
 
Most of the sockets are 6A, not 5A, so theoretical peak is 1320W. Also the amount of power you can draw is defined by how the wiring is done. If you don't have an appropriate circuit breaker in place, you can draw much more than 6A and it will be fine as long as the wiring is good quality/higher rating and the socket/plug are of reputed make.
 
cranky said:
I used to run a 4870x2 off a 5a wall socket and it melted the switches in three months.
Click to expand...

Ok that sounds scary! :eek:

Was it because of the bad socket or maybe some loose internals that was sparking? Because ideally, the 5A socket with (say a power factor rating of 0.8) would support 5 x 230 x 0.8 = 920W. And this system would have drawn way less power. Sounds a bit strange! In fact, I have my w/m plugged to a 5A socket and it has worked well till date for the last 8 months or so.

Do PCs draw a high initial current momentarily?

@Crazy_Eddy - tagging our in-house EEE guy.
 
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No, the 4870x2 was more hungry than the 6970 crossfire. I would measure peak usage close to 650W, though I also was using a Phenom 9950BE overclocked. That system was the most power hungry. The current one is quite a bit more powerful but about 10% more efficient.

One reason was cheap switches, the second was age and the third was power draw. Lesson learnt, i now replace points in high-criticality locations (audio/PC/Geysers) every three years regardless of condition.

I've noticed modulars tend to fare much more poorly than the old style rocker switches. In my Delhi apartment a modular would heat up after about 10 minutes of powering a 1 ton AC (a 15A switch, not 5).

@Lord Nemesis: No 6A socket will provide 1.3Kw and it is not at all recommended to operate electrical outlets at more than 50% of their rating for long periods of time. Theoretical limits and real-world performance are totally unrelated in Indian products.
 
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7950/7970 are pretty efficient and you can Crossfire them easily on a good quality 750/850W PSU. Corsair AX750/850 or Seasonic X-760/850 would do.
 
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