Is 750w enough?

[Shavako]

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?

 

[inzone]

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=N82E16817371049

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=N82E16817151107

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=N82E16817139025

Here are a few to look at.

 

[inzone]

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.

 

[Shavako]

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?

 

[truegenius]

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

 

[Shavako]

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.

 

[truegenius]

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

 

[Shavako]

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.

 

[Shavako]

Here's an Antec 900W 80 Plus Bronze. It's not modular but I guess that's something I'll just have to deal with if I want a quality PSU of that wattage at this price point. =/

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371050

 

[tlmck]

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=Property&Subcategory=58&Description=&Type=&N=100007657&IsNodeId=1&srchInDesc=&MinPrice=&MaxPrice=&OEMMark=0&Manufactory=1697&Manufactory=8484&Manufactory=1919&Manufactory=2031&Manufactory=1516&Manufactory=1459&Manufactory=9830&PropertyCodeValue=1314%3A58436

 

[Homeboy2]

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.

 

[Shavako]

This is what I'm going with: http://www.newegg.com/Product/Product.aspx?Item=N82E16817341044

Fully modular, 80+ Gold certified, quality manufacturer. Doesn't get much better than this for that price. (Which is pushing my budget up by about 50 dollars)

 

[Spoony]

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

 

[Shavako]

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.

 

[truegenius]

for a minimum 1000w is that i recommend

decision is yours

 

[Shavako]

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.

 

[davcon]

A quality 850W unit will handle your specs including a 2nd gpu in the future.

 

[tlmck]

I suggest everyone read my page on power supplies

http://www.hardcore-games.tk/wp/psu.php

That's quite good. Here is another.

http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061.html

 

[Shavako]

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)

 

[truegenius]

not including me 🙁

 

[Shavako]

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.

 

[truegenius]

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

 

[davcon]

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.

 

[Shavako]

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.

 

[truegenius]

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 ? not going to overclock gpu

seems like i misread it 😗

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:

😛 but you and others too haven't alerted me at that, i have stated both cpu and gpu overclocking in my posts