Enough power for crossfire?

xiorell

xiorell

xiorell

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Joined
19 May 2015
Posts
141
I had ruled it out with my current power supply but recently while I've been messing about it turns out, I might have enough power to crossfire a pair of r9 390s (non X versions) on a 750w psu. Apparently the load would work out to 680-690 watts.
I find this dubious at best so I thought I'd ask, is there enough power to go around for 2 r9 390s?

Here's the full build currently

MSI Z170a-G43
i5 6600k (running at stock 3.5ghz)
Sapphire r9 390 Nitro 8gb (at stock)
16GB DDR4 2400 (2x 8gb)
Sandisk 120gb SSD
1tb HDD
Pioneer DVD/CD
Corsair H100i v2
Aerocool 140mm DS fan x2
Aerocool 120mm DS Fan
EVGA 750 GQ Power Supply

-External kit

Corsair K70 RGB Keyboard
Corsair M65 RGB Mouse
Corsair VOID Wireless RGB
AOC G2460PF monitor (listed coz I have it hooked up to use the USB passthrough)
Xbox Wireless controller receiver

Sometimes I plug in a Saitek X52 Flight Control system, sometimes a Logitech G29 Wheel+Shifter
 
BluD said:
Ill give my system a quick measure if ya like and see how much it uses, i imagine 290x and 390s draw similar power.
Click to expand...

oh ok cool, if it's not to much trouble

Just if I have enough power as it is, I might actually throw in another GPU, if not I've a couple of other things I will chase :)
 
Your psu is able to output all of it's 750w on the 12v rail so that's good. While it should be ok as long as you don't overclock the cards the psu will be under heavy load and may be noisey as it will need to spin the fan up to cool the unit. I would prefer 850w to be safe, especially if you are going to overclock that 6600k at some point.

I would prefer a single gpu though as there is less chance of problems arising when compared to dual cards in crossfir/SLI and the potential issues that involves.
 
Lol your a good guesser, ill give you that xiorell.

I reset my system to stock speeds then ran a cpu bench to get the cpu to 100% and ran heaven to get both gpus to 100% and my power meter read a max of 691watts.

i think ill get you choosing my lottery numbers next week if thats ok. :)

edit, just ran it for a little longer to make sure and its topping out at 700 watts, given that theyre only 80% efficient i assume the demand on the 12v rail is a lot less, as im reading what its drawing from the wall.
 
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pastymuncher said:
Your psu is able to output all of it's 750w on the 12v rail so that's good. While it should be ok as long as you don't overclock the cards the psu will be under heavy load and may be noisey as it will need to spin the fan up to cool the unit. I would prefer 850w to be safe, especially if you are going to overclock that 6600k at some point.

I would prefer a single gpu though as there is less chance of problems arising when compared to dual cards in crossfir/SLI and the potential issues that involves.
Click to expand...

I'm not really planning on an overclock just yet so that side of it isn't an issue, though I have tested it out, the auto settings on the MB take it to 4.1 happily, I took it to the same manually when checking out the BIOS. Never tested beyond.

BluD said:
Lol your a good guesser, ill give you that xiorell.

I reset my system to stock speeds then ran a cpu bench to get the cpu to 100% and ran heaven to get both gpus to 100% and my power meter read a max of 691watts.

i think ill get you choosing my lottery numbers next week if thats ok.
Click to expand...

Is that all? See I was expecting more like 800w ish but then looking into, suprised to find a sub 700w draw.

Thanks for that, very illuminating.
I really suck at gambling tough, else I'd be sitting on 4way titans :D
 
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