750w enough for 6970 crossfire?

S

Sufu

[H]ard|Gawd
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Sep 3, 2006
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I am planning in adding a second 6970 for an eyefinity 5760x1200 setup, but I only have a Corsair HX750w PSU. Is this going to be enough?

Specs:
4x HDD (two in raid1)
1x DVD-DL burner
Core i7 @ 3.6
Intel 80GB SSD
6x 120MM fans,
a waterpump (only cpu is watercooled)
1x Auzentech Prelude Soundcard
1x Powercolor PCS+ 6970 videocard.
 
I will say that's borderline. Better off with at least a 900 or high PSU.
 
I'm looking at benches right now. It looks like you'd be pretty close, especially with all of your fans and drives. I'd get a 1000watt PSU. The last thing you want to do is skimp on power.
 
I'd get a 1200w PSU, but only because with CF'd 6970's you'd be in the load sweet spot for efficiency on a 80+ silver or gold PSU. The PSU probably wouldn't have to work so hard either which would mean it could run cooler and quieter and last longer depending on which model you get.

That may or may not be worth it to you because of the cost involved in getting a gold or silver 80+ 1200w PSU but its what I would do. Good luck either which way.
 
I kinda have similar hardware, but using two 6950s with the shaders unlocked, on a Seasonic 700 watt PSU. Been using it for a few months, haven't run into any problem.

Though maybe I'm driving my PSU into an early grave, haha. If so, it's had a good long life already.

* Intel Q9550 at 3.9GHz
* 2x XFX 6950s with shader unlock
* 2x OCZ Vertex 120GB SSDs
* 2x Velociraptor 300GB HDDs
* 2x WD Green 3TB HDDs
* Creative Xtreme Gamer
* Swiftech pump
* 4x 120mm Gentle Typhoon fans
* 1x 200mm Cooler Master fan
 
I'm running an I5 760 at 4ghz and 6950 crossfire that I regularly run at 900/1350 and I use a 650w psu with no issue. I don't see much over 500w while stress testing according to my UPS.

Unless you go for broke on the core voltage on those cards, overclock your cpu higher, and run Linpack and furmark at the same time you'll be fine.
 
BababooeyHTJ said:
Unless you go for broke on the core voltage on those cards, overclock your cpu higher, and run Linpack and furmark at the same time you'll be fine.
Click to expand...

This, if you keep Powertune at the stock setting so each card can only dram a maximum of 200 watts. That leaves enough for your other components during gaming.
 
I run unlocked 6950 crossfire (so essentially a 6970 crossfire) on a Corsair TX750 power supply.

you are good to go.
 
According to killawat my i5 with 6950 draws 205watt on load. Does second 6950 really quadruple the power draw?

edit: looking at Power Consumption charts, it looks like 6950 takes 256watts, so I am doing it wrong but still...
 
The 750 should be able to handle it, although I don't think it would be very good for it.
 
i'm on a 3+ year old 850 toughpower psu with two 6970 my max draw by power meter on my apc ups is about 660 watts so you would be close to max
i would go for a bigger psu,if buying now i would1000+ or a 1200 for future expansion
 
AMD lists the TX650 as crossfire compatible with 6970s. You should be fine.

http://sites.amd.com/us/game/produc...supplies.aspx?g=AMD Radeon™ HD 6970&p=Corsair

I understand the desire to be conservative with PSUs. It's important as one of the primary factors of system stability and reliability. A good 750 is fine.

Also those of you checking with a Killawatt or your UPS remember that is draw not output. PSUs should be rated are rated by output, not draw. That 660 watts bill_d is seeing means that his system is probably only outputting around 530 watts, Well into the butter zone.
 
You'll be perfectly fine. I'm running a Seasonic X750 and have:

-i7 920 @ 4GHz
-CFX 6950s unlocked and running at 1015MHz @ 1.28V each
-9 fans
-two MCP355 water pumps
-two WD blacks, two SSDs

My max power draw for the system is about 700W (after calculating .9 x wall draw).
 
I have the exact same PSU running a HD6970 crossfire setup without any problems. OCd i7 920 at 3.8 GHz, 12GB RAM, 2x SSD, 1x HD, 1x DVD, Asus Xonar SC, loads of fans an USB devices.

I think you will be fine.
 
I have the exact same question. I see this topic is a bit old... however, would a Corsair CX750M (80 Plus Bronze) be enough for a HD6970 crossfire setup? CX is not as fancy a series as the ones listed above, but it's a good deal at Micro Center and fits my case better then the HX850 Gold Certified one, which will block my intake 140mm fan by about 0.2 inches (I'd have to put a 120mm instead).

This would be in a AMD FX-8350 system, which is 125W, a higher wattage processor than i7's at 84W.
 
750 is plenty of 2x 6970 setup, i have an 825 enermax, and with an i7 920 @ 3.6 + 1x6990 and 1x 6970 and an antec 1200 with all fans going 4 hds, 1 dvd, 1 ssd, prelude xfi, i was pulling FROM THE WALL around 780w, meaning actual power draw was probably closer to 700-720w, so with 1 less 6970 to power you'll be fine on a 750
 
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