Sign in with
Sign up | Sign in
Your question

Is 750w enough?

Last response: in Components
Share
January 4, 2012 3:23:19 AM

Going to be building a PC soon and I'm not sure what size PSU I'll need. I used the calculator at http://extreme.outervision.com/PSUEngine and it says 655w minimum and 711 recommended so I was thinking 750W would be enough. Here's the components:

Gigabyte GA-Z68X-UD3H-B3
i5 2500k (Likely to be OCed @ 4.4ish, whatever OC Genie will get me to)
Corsair Vengeance 8GB 1600
HD 6970 and I might add a second one later (or 7970 if they're decently priced when they get released)
Cooler Master V6 heatsink
Seagate Barracuda 7200RPM 500GB
Samsung Blu-Ray combo
2x 200mm fans and 1 120mm
A couple code cathodes
Possibly a fan controller (only if fan noise is crazy which I doubt it will be)

The PSU I'm looking at is the OCZ Fatal1ty 750W 80 Plus Bronze Certified

Will that be enough power?

More about : 750w

a c 80 ) Power supply
January 4, 2012 3:53:06 AM

I agree with the 750w size as it looks like you are adding a few things like lights and fans and you may add more in the future. However I don't agree with the psu selection , I would go with Antec , Seasonic , or Corsair.

Antec High Current Gamer Series HCG-750 750W ATX12V v2.3 / EPS12V v2.91 SLI Certified CrossFire Certified 80 PLUS BRONZE Certified Active PFC Power Supply
$99.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

SeaSonic M12II 750 SS-750AM 750W ATX12V / EPS12V SLI Ready 80 PLUS BRONZE Certified Modular Active PFC Semi-modular Power Supply
$129.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

CORSAIR Gaming Series GS800 800W ATX12V v2.3 SLI Ready CrossFire Ready 80 PLUS Certified Active PFC High Performance Power Supply
$124.99 and a $5 rebate makes it $119.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Here are a few to look at.
m
0
l
a c 80 ) Power supply
January 4, 2012 3:57:08 AM

You can also get a higher watts psu if you choose to do so and you don't necessarily have to use all of the capacity of the psu but it is a good thing to have extra just in case. I don't believe in going with a psu that is just enough or good enough for what you have , that just resricts you to what you can add and if you want to add more components later on then you don't want to have to get another psu as well.
m
0
l
Related resources
January 4, 2012 4:09:56 AM

I like that 800W Corsair Gaming Series except that it's not modular. Is modular cabling really worth the extra money I'm going to pay to get a quality modular PSU?
m
0
l
a b ) Power supply
January 4, 2012 4:14:47 AM

4.4 is too hard to get
2xhd6970 2gb will require around 620w at full load at stock
and a i5 at 4ghz will require 150w
equals 770w
and other components will take 100w-150w
total 920w

thus i recommend 1000w or more with a combined continuious current of 70amp or more at 12v rail.

If you want to overclock your gpu too, then get a 1100w for 15% overclocked cards

seems too high than power calculator
m
0
l
January 4, 2012 4:57:10 AM

I've seen videos of people using the auto OC function in their bios and getting 4.6-4.7 so I doubt that 4.4 is that hard to get. I've read many posts where people are asking for a good PSU power calculator and the one that I use comes highly recommended.

No offense truegenius but I think your estimates are off by quite a bit.
m
0
l
a b ) Power supply
January 4, 2012 6:32:03 AM

trust me you need 1100w for duel hd6970+i5+overclocking

use these settings to calculate power
high end desktop
i5-2500k
100% tdp
overclock 5ghz@1.5v
2 ddr3 ram
gpu 1 amd hd6970
gpu 2 amd hd6970
1 high rpm sata
1 blu ray internal
fan controller
2 cathodes
1 120mm led fan
2 140mm high performance fan
system load 100%
capacitor aging 20%

and you will get a reading over 1000w, and we haven't overclocked gpus yet which will cause 60w increase per 10% overclock on stock voltage

trust me use these settings
m
0
l
January 4, 2012 6:48:42 AM

Why would I calculate the overclock at 5ghz at 1.5v when I don't plan to go over 4.5?
Why would I set it at 100% tdp and 100% system load when I'm not going to be at 100% load unless I'm running some benchmarks or something?
I've read from a few different sources that the capacitor aging extremely overstates how much power you will need, and isn't really useful anyway because if you buy a quality PSU you'll likely be replacing it before you need to worry about capacitor aging. Not to mention the PSU calculators already slightly overstate how much wattage you will need to compensate for manufacturers who put out PSUs that don't supply as many watts as they claim. 750W may be cutting it close but 850 should be more than enough.

Sorry but even though I'm a noob I'm sure your way off.
m
0
l
a b ) Power supply
January 4, 2012 7:14:22 AM

I agree that 1000w would be preferable. An old but very true rule of thumb is that you want at least a 30% cushion on a PSU under normal operating conditions. Throw in overclocking and whatnot and 50% is not unreasonable. As stated earlier in the thread, you do not have to use all the power. Besides, most of today's newer high quality units are made to be efficient at high and low loads. To that end, I would recommend anything on this list.

http://www.newegg.com/Product/ProductList.aspx?Submit=P...
m
0
l
January 4, 2012 7:47:16 AM

Shavako said:
I've seen videos of people using the auto OC function in their bios and getting 4.6-4.7 so I doubt that 4.4 is that hard to get. I've read many posts where people are asking for a good PSU power calculator and the one that I use comes highly recommended.

No offense truegenius but I think your estimates are off by quite a bit.

4.4 isn't hard to get, 850w quality PSU will be fine.
m
0
l
January 4, 2012 8:06:04 AM

plain and simple to run one 6970 yes its enough but if you add a 2nd card it WILL NOT be enough it WILL be extreme boarder line for being good enough for that setup 850w MINIMUM
m
0
l
January 4, 2012 8:12:13 AM

So I've got a couple people saying 850 is plenty and a couple saying I need more in the range of 1000W. I would think something like this would be pretty objective.
m
0
l
a b ) Power supply
January 4, 2012 8:39:15 AM

for a minimum 1000w is that i recommend

decision is yours
m
0
l
January 4, 2012 8:56:19 AM

You also said that 4.4ghz is hard to get, and then told me to set the cpu overclock to 5ghz when using the psu calculator. No offense but I've got to hear a recommendation for 1000w from some others.
m
0
l
a c 274 ) Power supply
January 4, 2012 12:43:59 PM

A quality 850W unit will handle your specs including a 2nd gpu in the future.
m
0
l
January 4, 2012 2:40:13 PM

Well those are great articles and now I know a little more about how power supplies work but I still don't know how much power I'll need. It seems I have 3 votes for ~850 and 1 for ~1000 (not including truegenius)
m
0
l
a b ) Power supply
January 4, 2012 2:51:58 PM

not including me :( 
m
0
l
January 4, 2012 2:57:48 PM

Sorry but I can't respect your opinion based on other things you've said. You may be right but I'm getting mixed answers right now. I'm fairly certain that 850 is going to be enough anyway as I've gotten that answer from more people and the psu calculator produced a recommended wattage of 711W.
m
0
l
a b ) Power supply
January 4, 2012 3:04:17 PM

Shavako said:
Sorry but I can't respect your opinion based on other things you've said. You may be right but I'm getting mixed answers right now. I'm fairly certain that 850 is going to be enough anyway as I've gotten that answer from more people and the psu calculator produced a recommended wattage of 711W.


850w is enough for stock, but you have stated overclocking and for that 850 is not enough :ange: 
m
0
l
a c 274 ) Power supply
January 4, 2012 3:14:48 PM

850w is fine for 2 x 6970 most testbeds using o'cd i7 9xx's use @ 600W = full system power load
So 850w is a very good choice.
m
0
l
January 4, 2012 3:14:54 PM

Yes but you also said you ran the PSU calculator setting the CPU to 5Ghz at 1.5v and used 20% capacitor aging which I've read is completely unnecessary. I don't overclock for "sport" so there's no reason for me to OC that high and from what I've been told that you can reach ~4.2 just by changing the multiplier so I doubt I'll need anywhere near 1.5V to hit ~4.4 if I decide to go that high. Also I don't really plan to overclock the GPUs and the one's I'm looking at for now have a very light factory OC (<5%)

Edit: I'm going to go with Davcon here and agree that 850W should be plenty and still give me some headroom. I just can't see why I would need 1000W+ for this setup. Going with the OCZ ZX Series 850W 80 Plus Gold.
m
0
l
a b ) Power supply
January 4, 2012 3:35:37 PM

Shavako said:
Yes but you also said you ran the PSU calculator setting the CPU to 5Ghz at 1.5v and used 20% capacitor aging which I've read is completely unnecessary. I don't overclock for "sport" so there's no reason for me to OC that high and from what I've been told that you can reach ~4.2 just by changing the multiplier so I doubt I'll need anywhere near 1.5V to hit ~4.4 if I decide to go that high. Also I don't really plan to overclock the GPUs and the one's I'm looking at for now have a very light factory OC (<5%)

Edit: I'm going to go with Davcon here and agree that 850W should be plenty and still give me some headroom. I just can't see why I would need 1000W+ for this setup. Going with the OCZ ZX Series 850W 80 Plus Gold.


5ghz@1.5v only adds 50-60 w to system

what :ouch:  ? not going to overclock gpu

seems like i misread it :whistle: 

if you want to overclock i5 to 4.4 only and do not want to overclock your graphics cards then you can go with 850w :lol: 

:p  but you and others too haven't alerted me at that, i have stated both cpu and gpu overclocking in my posts
m
0
l
January 4, 2012 4:00:13 PM

Like I said I meant no disrespect as you probably know a lot more than I, I just thought 1000W sounded a little overboard. I guess I didn't notice that you were including a GPU OC. I'm glad we can agree that 850W seems to be enough :) 

But yeah, the GPU I'm looking at has a light overclock already which should be enough for me. By the time I would need to give it a big OC I'm pretty sure I'll be ok with spending the money for a new card lol.

I think it also helps a lot that the PSU I'm going with is Gold Rated. Thanks for helping even though we were a little off que on my plans ;) 
m
0
l
January 4, 2012 5:18:46 PM

$190 is just too much for a PSU. The OCZ is already pushing my budget up at $170 and it's also 80Plus Gold rated.
m
0
l
a c 80 ) Power supply
January 4, 2012 5:26:50 PM

Shavako said:
Like I said I meant no disrespect as you probably know a lot more than I, I just thought 1000W sounded a little overboard. I guess I didn't notice that you were including a GPU OC. I'm glad we can agree that 850W seems to be enough :) 

But yeah, the GPU I'm looking at has a light overclock already which should be enough for me. By the time I would need to give it a big OC I'm pretty sure I'll be ok with spending the money for a new card lol.

I think it also helps a lot that the PSU I'm going with is Gold Rated. Thanks for helping even though we were a little off que on my plans ;) 



I think that you had a good choice when you posted the Antec 900w, I have not heard a lot of good things about OCZ power supplies and to be honest I believe you should be choosing between Antec, Seasonic and Corsair. The 850w to 900w range is a good choice and as I have said many times you can always get more power supply than you need , after all you are the one buying it and I totally disagree with anyone saying you only need a certian amount and there's no need to go with that high of a psu and you should be fine with a lower watts psu. They are not the one buying it you are so you can get whatever you want to. You could get a 1200w psu if you wanted to spend that much money , it's your computer , put what you want , you don't have to justify to anyone what you want to buy. You just never know what you are going to do or add to your pc.

Antec High Current Gamer Series HCG-900 900W ATX12V v2.3 / EPS12V v2.91 SLI Certified CrossFire Certified 80 PLUS BRONZE Certified Active PFC Power Supply
$129.99
m
0
l
a c 80 ) Power supply
January 4, 2012 5:32:15 PM

SeaSonic M12II 850 SS-850AM 850W ATX12V / EPS12V SLI Ready 80 PLUS BRONZE Certified Modular Active PFC Semi-modular Power Supply
$149.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

CORSAIR Professional Series HX850 (CMPSU-850HX) 850W ATX12V 2.3 / EPS12V 2.91 80 PLUS SILVER Certified Modular Active PFC Power Supply
$169.99 and a $20 rebate makes it $149.99
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Here are a couple of good quality 850w psu's for $150.
m
0
l
January 4, 2012 6:48:20 PM

Yeah I forgot about that Antec 900W Gamer Series. I wish it was modular but it's a good price. Is it worth the extra $30 or more I'm going to pay for a quality 850-900w PSU for modular cabling? I only ask because I've never worked with a modular PSU.
m
0
l
January 4, 2012 7:21:00 PM

Modular add $50 to the price of a PSU or more

That is why the TX850 is available for those who do not mind the standard octopus
m
0
l
January 4, 2012 7:32:14 PM

The PSU I have now isn't modular and I didn't mind it. It also had very few connections because it's a crappy ePower 550W. I would eventually be using all of the PCI connections on the TX850 but there would be at least 6 SATA power cables left over but it might be alright. I don't want to regret not getting modular though. And it could add $50 dollars more but not necessarily the TX is $134 and the HX is $169. That's only $35 more which may be worth it for modular cabling and it's Silver rated compared to the Bronze rated TX.
m
0
l
January 4, 2012 7:48:13 PM

The TX850 is the one you want, 70A on the 12V line can handle the video cards you buy reasonably well even overclocked

The ads on my site are automatic best price, that is why I selected them

The PSUs are all screen to be respectable
m
0
l
a c 1167 ) Power supply
January 4, 2012 8:04:58 PM

veganfanatic said:
Modular add $50 to the price of a PSU or more

That is why the TX850 is available for those who do not mind the standard octopus

But there's a CORSAIR Enthusiast Series TX850M 850W which is semi-modular and sells for $139.99 at Newegg.com. It's only $5 more than the standard fully hardwired model.
m
0
l
January 4, 2012 8:08:34 PM

I found modular cables can be dodgy with a high load. Mainly due to oxidation. Soldered wire does not.
m
0
l
January 4, 2012 8:09:17 PM

vibration is a nightmare in a computer
m
0
l
a b ) Power supply
January 4, 2012 8:23:12 PM

750W is borderline, 850W is safe.
m
0
l
a b ) Power supply
January 4, 2012 8:24:01 PM

veganfanatic said:
I found modular cables can be dodgy with a high load. Mainly due to oxidation. Soldered wire does not.


Quality units have gilded connectors AFAIK.
m
0
l
January 4, 2012 9:08:28 PM

the problem is fan vibration can abrade the gold plate, after a couple of years its not doing so good

I am thinking the TX850 is a good value for the $
m
0
l
a c 1167 ) Power supply
January 4, 2012 10:03:50 PM

veganfanatic said:
the problem is fan vibration can abrade the gold plate, after a couple of years its not doing so good

I am thinking the TX850 is a good value for the $

Do you have the data or the links to sources to back that up?
m
0
l
January 4, 2012 10:10:33 PM

Look it up in Google, vibration can do all kinds of unwanted things

The TX850 has a 5 year warranty and it likely will last much longer. Mainly due to good capacitors. I assume the machine is clean.
m
0
l
a c 243 ) Power supply
January 4, 2012 10:18:57 PM

veganfanatic said:
Look it up in Google, vibration can do all kinds of unwanted things

Look it up in Google ? You should be able to provide the evidence to back up what you claim.

You do realize that those vibrations would act the same on the connectors of a non-modular psu don't you ?
Maybe all connections should be soldered, would make upgrading a video card hell , no ?

PS; Corsairs modular TXM has a 5 year warranty and the HX units have a 7 year warranty
m
0
l
a c 1167 ) Power supply
January 4, 2012 10:19:54 PM

veganfanatic said:
Look it up in Google, vibration can do all kinds of unwanted things

The TX850 has a 5 year warranty and it likely will last much longer. Mainly due to good capacitors. I assume the machine is clean.

So what you have is conjecture without proof. If the problem truly existed, as you seem to believe, then there would be a spate of this problem being reported and yet it doesn't seem to exist.

Vibration also causes unwanted noise, but so what?
m
0
l
January 4, 2012 10:27:11 PM

that noise can feed back on a 12V line causing ripple etc
m
0
l
!