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750w enough?

NoobCannon

NoobCannon

NoobCannon

Soldato
Joined
13 Jun 2011
Posts
6,053
hi all,

think im having some psu problems, my psu is an Antec high current gamer
750w

bS2Tjju.jpg

my system specs are

i7 3770k @ 4.7
2 x 7970 1200/1700

it seems that when my gcards are fully loaded in bf3 for an example and the fan starts to ramp up on the psu [rest of pc is watercooled] sometimes the screen starts to spam out and artifacts.

never happens on valley and never happens if I run a frame limiter.

is it possible that my psu is crapping out once my cards are running flat out?

Steve
 
I would say so as 750 is cutting it really fine,especially with those overclocks as well. It would make sense that with the limiter on its managing but when you allow it to draw more power it craps out. I would say 1000wt and I know it may be overkill but for the same set-up I had a ax1200i. IMO you should always have a bit of headroom so your not having it flat out all the time. I would say that if its the PSU'S fault or not you should have a larger one.
 
I would have thought a 750w psu would be fine. I got told on here that a 750w would be fine for sli 780, and iirc, both 780 and 7970 are in a similar boat power wise. Someone may correct me on this though.

Edit: Guess I was a little slow typing there.
 
Highly overclocked i7 and pair of high overclocked 7970 would be pushing it for a 750W PSU, even if the Antec really can push 750W over the 12v rail as they claim.

IMO if I were in your shoe, if those 7970s' voltage can be adjusted, I'd just drop them down to 1100MHz and find the lower stable voltage for them. The extra 100MHz ain't gonna make a huge real-world difference...

The CPU I might considering dropping down to 4.60GHz and find a lower vcore as well.

One thing you have to remember is that Valley Bench don't really put load onto your CPU as games do.
 
That unit is decent, it could just be a case of you overloading the rails, two 7970s running full pelt is a high ask to run off each of those rails. 750W on a single 12v rail PSU would run your rig no worry.
 
thanks for everyones replys, can any of you recommend a replacement psu?

would like to carry on running my system at these clocks, after spending a fortune on watercooling I don't plan on underclocking/lowering clocks on anything lol
 
mate why not spend twenty quid on a power-draw plug so you can see how much you are pulling from the wall?

They are great fun for the present/future and may give you an idea if you are near your PSU limit.
 
3t3P said:
mate why not spend twenty quid on a power-draw plug so you can see how much you are pulling from the wall?

They are great fun for the present/future and may give you an idea if you are near your PSU limit.
Click to expand...
No need, his PSU is clearly struggling.

Here a system with i7 3770K overclocked to 4.80GHz running just prime 95 power consumption 244W at load:
http://www.bit-tech.net/hardware/2012/04/23/intel-core-i7-3770k-review/8

And a stock 7970 at 925MHz power consumption 270W max:
http://www.techpowerup.com/reviews/AMD/HD_7970/26.html

Do the math :p And PSU in general won't be very effcient once pushed beyond 90% load.
 
doesn't efficiency means that will take more from the wall and not give less to components? For instance, 75% load, 90 eff. (563W for components - 625W from the wall / 750W for components, 80% eff - 938W from the wall).

Not being able to give the advertised power to components, happens usually over time, while the PSU itself gets older.

Anyway, jumps in power consumption should be pretty big once you touch the voltages. It's around 50-80W on my 7950, can't remember exactly anymore.
 
Calin Banc said:
doesn't efficiency means that will take more from the wall and not give less to components? For instance, 75% load, 90 eff. (563W for components - 625W from the wall / 750W for components, 80% eff - 938W from the wall).

Not being able to give the advertised power to components, happens usually over time, while the PSU itself gets older.

Anyway, jumps in power consumption should be pretty big once you touch the voltages. It's around 50-80W on my 7950, can't remember exactly anymore.
Click to expand...
That's not what I meant. For most PSU, once they reach over 90% load, the unit would become so hot, that the fan will ramp up to such a high rpm and become quite noisy.
 
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