750w enough?

M

manny1222

Gawd
Joined
Mar 11, 2012
Messages
732
I have had to RMA my video card twice, and I'm frankly starting to wonder if my power supply is the problem. I current own an Antec HCG 750W that I picked up from the for sale section. I'm in the process of upgrading my card from a 670 FTW to a 680 FTW (just waiting for the card to get here). I'm thinking of possibly picking up a corsair psu with my next paycheck because of their reliability. My system specs are in my sig. My question is would 750W be enough for all I have currently, plus a second 680 FTW and a custom WC loop? (Hoping to save up money for those and cram them into my HAF 912).
I'm currently considering the AX 750 here, but it's really just above my budget of $150.
If 750w is not enough, then I'd probably go with the HX 850 here.
I would really rather have the AX 750 because of the higher efficiency, fully modular and slightly smaller size that may allow me to stick a second 240mm radiator on the bottom of my case.
 
A pair of 680s can pull about 450 watts max. Your OCed 2500K is prolly pulling 175-200 watts. So you have about 100 watts to play with for everything else.

Efficiency shouldn't be your deciding factor as they are both 80 plus Gold and should have very similar efficiency numbers. If I were in your position, I'd grab the HX850 just to have abit more headroom, especially since you plan on WCing.
 
Wit that much draw, you might not need more than 750w, just get one with a good efficiency rating.
 
I'd get an 850W unit, simply because you're looking at running the PSU at close to 90% capacity when gaming on a 750W PSU and you don't want to have so little headroom for the future.
 
That's a below <600W system at full load, the 750W AX is already overkill... going for 850W is pointless, and a no return investment.
 
manny1222 said:
Okay! Still differing views. Exactly my dilemma.
Click to expand...

How serious are you about getting SLI? With a single card a 550W PSU would be fine, add a second and you need another 250W. I ask as lots of folks buy way more than they need in the PSU department with plans to get CFX or SLI, and end up never using it. Like for example me, I got a 750W intending to in the future get 2x6850s (when I had a single 6850)-and I never did and went straight to a higher power single card to avoid multi-card stutter and driver issues.

A water loop adds little in extra load. Most individual water pumps only pull 15-20W.
 
Skripka said:
How serious are you about getting SLI? With a single card a 550W PSU would be fine, add a second and you need another 250W. I ask as lots of folks buy way more than they need in the PSU department with plans to get CFX or SLI, and end up never using it. Like for example me, I got a 750W intending to in the future get 2x6850s (when I had a single 6850)-and I never did and went straight to a higher power single card to avoid multi-card stutter and driver issues.

A water loop adds little in extra load. Most individual water pumps only pull 15-20W.
Click to expand...

Using the extreme psu calculator, I also came up with 550W, with 600W recommended. It is my intention to get a second 680. I don't know how soon it'll be. It took me a while to save up to get this one, but I'm hoping by the holiday season with christmas sales and stuff, I'll be able to cough up the $600 (or less) I need for it. Unless the 680 is able to give me the performance I want on my surround with three 26 inch monitors. It is EVGA GTX 680 FTW 4GB.
 
The Keplers are extremely efficient. A 750W PSU will be completely fine for 2*GTX 680 even with a heavily OCed hex-core i7. The Antec HCG 750W is a decent PSU, shouldn't have any issues with it. Frankly, IMO the most sensitive component in a PC is the HDD, if you've got a bad PSU then the HDD will be the first component that require RMA.
 
Find out how much power your computer is pulling from the wall while you are running a graphics benchmark such as furmark. you can use a modified small extension cord and a clamp on meter for this. Times amps by voltage and you get watts.

If the number is 50-100w lower than the rating of your PSU you are doing fine. Keep in mind the draw at the wall is higher than the draw from the PSU itself. It's just easier to measure it at the wall.

Lot of video cards today need like 400w so if you have two you are already at 800w. But often these ratings are very over estimated so best to just test it yourself.

A good quality PSU is better than even the highest wattage crappy quality one.
 
Get a wall meter and measure it. There is no reason to engage in pointless debate. They cost $20 and you can use it for many other applications to test power usage.
 
MrDudeMan said:
Get a wall meter and measure it. There is no reason to engage in pointless debate. They cost $20 and you can use it for many other applications to test power usage.
Click to expand...

And most wall meters are at best wild guesses. You can buy two Kill-a-Watts from the exact same factory batch numbers...and get wildly different readings.
 
Skripka said:
And most wall meters are at best wild guesses. You can buy two Kill-a-Watts from the exact same factory batch numbers...and get wildly different readings.
Click to expand...

Wow really? That kinda defeats their purpose lol. I've been trying to find a place that has them, guess I wont bother, I'll stick to my clamp on meter method. :D Though I sometimes wonder if that really is that accurate as if the meter is not true RMS the amp reading can be off too. That's probably the issue with the kill-a-watts.
 
Red Squirrel said:
Wow really? That kinda defeats their purpose lol. I've been trying to find a place that has them, guess I wont bother, I'll stick to my clamp on meter method. :D Though I sometimes wonder if that really is that accurate as if the meter is not true RMS the amp reading can be off too. That's probably the issue with the kill-a-watts.
Click to expand...

Manyof the lead PSU gurus on the net @ [H] and JonnyGuru have taken issue specifically with KaWs. The general conclusion is that to get a really consistent accurate measurement you need to spend more than your computer is probably worth.

DannyBui collected many of the linkies and statements about em in this post here:

http://hardforum.com/showpost.php?p=1035698442&postcount=6
 
davidduc said:
The Keplers are extremely efficient. A 750W PSU will be completely fine for 2*GTX 680 even with a heavily OCed hex-core i7. The Antec HCG 750W is a decent PSU, shouldn't have any issues with it. Frankly, IMO the most sensitive component in a PC is the HDD, if you've got a bad PSU then the HDD will be the first component that require RMA.
Click to expand...

An i7 and two GTX 680's would consume ~520W without any overclocking (and the FTW version does use additional power but I don't know how much more), and without figuring in wattage consumed by other components of the system . Yes, it would be close. Doable. But I personally don't like to push my PSUs to 90% of capacity; 80% is fine, 50-60% is better. Not 90%. It'll last longer if you aren't pushing it as hard.
 
davidduc said:
........Frankly, IMO the most sensitive component in a PC is the HDD, if you've got a bad PSU then the HDD will be the first component that require RMA.
Click to expand...


I had a Seagate 1.5TB HDD go bad about 6 weeks ago. Replaced it with a caviar black.750GB which is still working fine. I wanna replace both the psu and memory to make sure that those don't mess up a $600 (or $1200 as the case might be) gpu. I can't think of what else it could be.
 
night_2004 said:
An i7 and two GTX 680's would consume ~520W without any overclocking (and the FTW version does use additional power but I don't know how much more), and without figuring in wattage consumed by other components of the system . Yes, it would be close. Doable. But I personally don't like to push my PSUs to 90% of capacity; 80% is fine, 50-60% is better. Not 90%. It'll last longer if you aren't pushing it as hard.
Click to expand...
Assuming that OCing and other components will be able to make that build to reach 650w then what ? 650 is only 86% of 750. PSU ratings are continuous load, not peak load. And you will only be able to reach that load under extreme condition: cpu and vid cards are fully loaded simultaneously, which is a rare circumstance. Most PSU are fine when working at 90% of its capacity 24/7 and they are designed to do it w/o problems.

50-60% load is better ? Gimme a break. You will need a 3 kW PSU for a tri-sli dual socket setup while you can run it perfectly safe with a 1.2kw PSU. LOL. Used to ran my system with 470 & 480 for folding (3 clients: 2 * GPU and 1 * SMP4) on the PC P&P Quad 750 for around a month, gave up because of the noise, not the PSU that can't handle it.

@manny: It's very unlikely that your current PSU is the cause of the vid cards' death. Still, if you insist on replacing your PSU, the AX750 is a solid one, get it and forget about upgrading your PSU unless you want to go tri-sli :D
 
Last edited:
cpu and vid cards are fully loaded simultaneously, which is a rare circumstance. Most PSU are fine when working at 90% of its capacity 24/7 and they are designed to do it w/o problems.
Click to expand...

That's something I keep forgetting about. I frequently load both the CPU and GPU so I tend to be a bit conservative on PSU purchases.

davidduc said:
50-60% load is better ? Gimme a break.
Click to expand...

Just a personal preference from a heat and fan noise point of view. As you pointed out the fan can get quite loud when the PSU is running at near full capacity.
 
Red Squirrel said:
Find out how much power your computer is pulling from the wall while you are running a graphics benchmark such as furmark. you can use a modified small extension cord and a clamp on meter for this. Times amps by voltage and you get watts.

If the number is 50-100w lower than the rating of your PSU you are doing fine. Keep in mind the draw at the wall is higher than the draw from the PSU itself. It's just easier to measure it at the wall.

Lot of video cards today need like 400w so if you have two you are already at 800w. But often these ratings are very over estimated so best to just test it yourself.

A good quality PSU is better than even the highest wattage crappy quality one.
Click to expand...

No current gen video cards need 400w, including the GTX 690 which only needs about 375. Your numbers are completely out of whack.
 
Jorona said:
No current gen video cards need 400w, including the GTX 690 which only needs about 375. Your numbers are completely out of whack.
Click to expand...

I was saying what the manufacturer says, not what they actually use. The manufacturers are very conservative, as I mentioned. They give much bigger numbers than what they actually use. I have a GTX 560 and the manual says 400w minimum. Though in reality my PC only uses about 300-400w when I max it out, with two of those cards.
 
Red Squirrel said:
I was saying what the manufacturer says, not what they actually use. The manufacturers are very conservative, as I mentioned. They give much bigger numbers than what they actually use. I have a GTX 560 and the manual says 400w minimum. Though in reality my PC only uses about 300-400w when I max it out, with two of those cards.
Click to expand...

400w minimum includes all components, so 2 vid cards doesn't mean double that. I think that's the point he was making you aware off
 
davidduc said:
......

@manny: It's very unlikely that your current PSU is the cause of the vid cards' death. Still, if you insist on replacing your PSU, the AX750 is a solid one, get it and forget about upgrading your PSU unless you want to go tri-sli :D
Click to expand...


Just trying to eliminate the usual suspects. One HDD and 2 gpu RMA. Don't want to waste $600.
 
You must log in or register to reply here.
Back
Top