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Selecting a PSU using PSU calculators

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December 7, 2012 3:12:39 PM

As the title says, I am currently selecting a PSU to use for my new build. You can see the details for this build here: Budget AM3+ for Office and Light Gaming

I designed by rig so that it's inexpensive now, but can have more components added as time goes on. Starting out, I will have use a HD 7750 GPU, 8 GB of RAM, and a 965 BE CPU. I plan to have a final build using a 7770 or 7750 crossfired with the original GPU, 16 GB of RAM, and a late model Bulldozer/FX CPU.

Entering the info into the OuterVision and NewEgg PSU calculators yielded the following information:

New Build:
OuterVision minimum: 334 watts
NewEgg recommended: 354 watts
OuterVision recommended: 384 watts

Final Build:
OuterVision minimum: 445 watts
NewEgg recommended: 491 watts
OuterVision recommended: 495 watts

So assuming the margin of error used in the recommended values is sufficient, looks like I should be good to go with a 500 watt unit, eh?

Obviously everyone wants a reliable unit for the best price, but I'm also interested on saving on the electricity bill, so 80 PLUS certification is a requirement, though it seems most are nowadays, anyway. As far as particular PSU models are concerned, I discovered this list of recommended units: A list of recommended PSUs

So here are the three primary contenders, in $$$ order:
1) Rosewill RG530 S12
ATNG made. 41 amps 12V. $49.99 and 2 year warranty ($25.00/year). (Regular) 80 PLUS.

2) Antec Neo Eco 520C
Seasonic made. 40 amps 12V power. $54.99 and 3 yr warranty ($18.33/year). (Regular) 80 PLUS.

3) Seasonic 520W S12II
Seasonic. 40A. $67.99 and 5 year warranty ($13.60/year). 80 PLUS Bronze.

So is there that much difference between regular 80 PLUS and Bronze, in terms of utility bill savings? From what I've read (briefly), it seems there isn't; the power savings is mostly seen in a large-scale corporate setting. I think the primary benefit of the increasingly expensive units is the extension of warranty, especially the 5-year on the Seasonic. In terms of per-year warranty value, the Seasonic is actually the cheapest!

Any comments/suggestions? This is my first build and I'd like to do it right the first time. Thanks!
a b ) Power supply
December 7, 2012 4:17:17 PM

I like the seasonic 520W. Keep in mind those calculators overestimate what you need to be safe. If you are going to crossfire you shouldn't get 2 cards that weak. The seasonic would be able to power 7770 cf though, assuming it has the right connectors.
Related resources
December 7, 2012 5:09:57 PM

Seasonic.
Best supplier of PSU's in existence.
a b ) Power supply
December 7, 2012 5:19:33 PM

The Seasonic is great, but too expensive IMHO. I'd get the Antec out of those three. Though that Rosewill RG630 is a nice bargain.
December 8, 2012 1:45:58 PM

Thanks for the comments, everyone.

wanderer11 said:
I like the seasonic 520W. Keep in mind those calculators overestimate what you need to be safe. If you are going to crossfire you shouldn't get 2 cards that weak. The seasonic would be able to power 7770 cf though, assuming it has the right connectors.


I'm thinking about Crossfiring two 7770's, now, actually. Here's what the calculators estimate for that setup:

Crossfired 7770's:
OuterVision minimum: 490 watts
NewEgg recommended: 523 watts
OuterVision recommended: 540 watts

So the calculators are conservative enough to still feel good about a 520 watt unit?

I've been hearing really great things about Seasonic, so I think I'm going to go with that one. Even though it costs more, it really makes sense to me when you view it as cost/warranty years. It seems like it will be the best investment.

Regarding connectors: "With one 6-pin and one 6+2 pin PCI-E connectors, the SeaSonic S12II 520 Bronze allows you to build up a SLI or CrossFire gaming system."

NOW I just need to figure out which particular HD 7770 I want to buy!
a c 243 ) Power supply
December 8, 2012 2:01:25 PM

trumpmech said:


3) Seasonic 520W S12II
Seasonic. 40A. $67.99 and 5 year warranty ($13.60/year). 80 PLUS Bronze.

So is there that much difference between regular 80 PLUS and Bronze, in terms of utility bill savings? From what I've read (briefly), it seems there isn't; the power savings is mostly seen in a large-scale corporate setting. I think the primary benefit of the increasingly expensive units is the extension of warranty, especially the 5-year on the Seasonic. In terms of per-year warranty value, the Seasonic is actually the cheapest!

Any comments/suggestions?

Shipping cost put's it at close to $78
You can go modular for $80
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Or get another 100 watts ( future proofing ? )
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
December 8, 2012 2:18:30 PM

delluser1 said:
Shipping cost put's it at close to $78
You can go modular for $80
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Or get another 100 watts ( future proofing ? )
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Wow, thanks for the suggestions! I didn't think about the shipping cost, but it's a no-brainer to upgrade to one of those!

One question: Say your actual load/use was 400 watts. Would a 520 watt and a 620 watt PSU each draw about 500 watts from the wall, or would they use 650 watts and 775 watts, respectively, no matter what your need was?

(Calculations were based on (rated watts) / (80% efficiency) = real watts.)

I ask because I want to know if upgrading to a 620 watt unit would make a noticeable effect on the electric bill for the same given power need by the system, or if they would draw similar power from the wall, one just has a higher max?
a c 243 ) Power supply
December 8, 2012 2:44:45 PM

The efficiency levels between them ( the Seasonics ) are similar enough that it's unlikely that there would be a difference in the power draw from the wall, if there were it would be minimal ( 1-2% )
December 8, 2012 2:51:21 PM

delluser1 said:
The efficiency levels between them ( the Seasonics ) are similar enough that it's unlikely that there would be a difference in the power draw from the wall, if there were it would be minimal ( 1-2% )


I see. So there's really no detriment to getting a higher-wattage unit besides cost, then? I guess I thought that a higher-watt unit would always draw more power than the lower-watt unit for a given load, and that the difference would be similar to the difference in rated wattage (not 1-2%). But apparently that was wrong. I'm definitely new to all this, and am just trying to absorb as much information as I can.

I really think I will (eventually) end up with a crossfired 7770 setup, so if that is good to go with a 520 watt unit I think I will just go with the modular Seasonic 520 Bronze, since I've read that cable management (and general hassle) is nicer with a modular unit.
December 8, 2012 2:59:04 PM

trumpmech said:
I see. So there's really no detriment to getting a higher-wattage unit besides cost, then? I guess I thought that a higher-watt unit would always draw more power than the lower-watt unit for a given load, and that the difference would be similar to the difference in rated wattage (not 1-2%). But apparently that was wrong. I'm definitely new to all this, and am just trying to absorb as much information as I can.

I really think I will (eventually) end up with a crossfired 7770 setup, so if that is good to go with a 520 watt unit I think I will just go with the modular Seasonic 520 Bronze, since I've read that cable management (and general hassle) is nicer with a modular unit.


Meh. I would save money with a RG630 and go for a better GPU. Crossfiring low end cards is never worth it.
December 8, 2012 3:21:45 PM

samuelspark said:
Meh. I would save money with a RG630 and go for a better GPU. Crossfiring low end cards is never worth it.


Never is a pretty strong word. Do you have particular reasons/numbers to support that? I've seen charts that show that crossfiring two 7770s results in almost (but not quite) double the performance of a single 7770. I realize that two 7770's are more expensive than one card of the same performance would be. But the essence of my build is saving money in the easily expandable areas right now (RAM, GPU, etc- things you can snap in and out easily), but investing in the backbone of the system (motherboard, PSU, etc- more "permanent" pieces) so I don't have to mess with those later.

I also really like the heat/power aspects of the 7750/7770, though I have been persuaded to forget about the 7750 due to performance and the 7770 not costing much more, now. I certainly am not trying to make a "silent" system, but considering how loud my current laptop fans are now (it uses a hot Pentium 4), I'd like to make a system that is reasonably quiet.

You certainly are not alone in your viewpoint (crossfiring isn't worth it), so I'm not trying to say that. Based on my needs (see link at top), I'm thinking an "okay" single card like a 7770 will probably do me for a while, but I want to have the option to expand with a second card "just for the fun of it" later. Then again, I may, in the future, decide to just buy a more expensive card at that point rather than buying a second of my original card (which is what you're suggesting, just delayed in time).
December 8, 2012 4:16:12 PM

trumpmech said:
Never is a pretty strong word. Do you have particular reasons/numbers to support that? I've seen charts that show that crossfiring two 7770s results in almost (but not quite) double the performance of a single 7770. I realize that two 7770's are more expensive than one card of the same performance would be. But the essence of my build is saving money in the easily expandable areas right now (RAM, GPU, etc- things you can snap in and out easily), but investing in the backbone of the system (motherboard, PSU, etc- more "permanent" pieces) so I don't have to mess with those later.

I also really like the heat/power aspects of the 7750/7770, though I have been persuaded to forget about the 7750 due to performance and the 7770 not costing much more, now. I certainly am not trying to make a "silent" system, but considering how loud my current laptop fans are now (it uses a hot Pentium 4), I'd like to make a system that is reasonably quiet.

You certainly are not alone in your viewpoint (crossfiring isn't worth it), so I'm not trying to say that. Based on my needs (see link at top), I'm thinking an "okay" single card like a 7770 will probably do me for a while, but I want to have the option to expand with a second card "just for the fun of it" later. Then again, I may, in the future, decide to just buy a more expensive card at that point rather than buying a second of my original card (which is what you're suggesting, just delayed in time).


Yes, microstuttering is annoying and you probably won't get another 7770 the 8XXX series are due in a couple of months. There's no reason to overspend on the PSU. The RG630 is excellent for the price. Besides, if you spend the extra $50 for a 7850 now, you won't have to spend the extra $120 later for a 7770.
December 8, 2012 4:36:24 PM

samuelspark said:
Yes, microstuttering is annoying and you probably won't get another 7770 the 8XXX series are due in a couple of months. There's no reason to overspend on the PSU. The RG630 is excellent for the price. Besides, if you spend the extra $50 for a 7850 now, you won't have to spend the extra $120 later for a 7770.


Ah, yes. Microstuttering. I remember reading about that, now that you mention it.

Browsing NewEgg:
So the 7770s are all 128-bit/1GB while the 7850s are 256-bit and either 1 or 2GB; I see that processing power is noticeably greater for the 7850. Looks like the 2GB models generally run $40-50 more than the 1GB models.

So based on the price you stated, I'm inferring you are suggesting I go with a 1GB 7850? Any particular brand/model?

Sorting by rating, the top two on NewEgg were:
XFX Double D FX-785A-CDFC Radeon HD 7850 2GB - $209.99 ($179.99 after rebate)
SAPPHIRE 100355-1GOCL Radeon HD 7850 1GB - $174.99 ($159.99 after rebate)

I've heard some companies (XFX, maybe others) can be shady when it comes to rebates, though.
December 8, 2012 6:19:20 PM

samuelspark said:
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Cheapest 2GB 7850.

Honestly doesn't really matter which 7850 you get. I generally go for the cheapest high performing one.


Now I'm starting to wonder about your suggestions, a little. For both PSU and GPU you're recommending the cheapest unit at the desired performance level. Does quality and reliability not factor into the equation at all? :heink: 

By the way, after rebates, the XFX I posted is only $5 more than the one you posted. Its reviews are clearly better, so if I end up going with a 7850, I'll probably go with that.
December 8, 2012 6:36:55 PM

trumpmech said:
Now I'm starting to wonder about your suggestions, a little. For both PSU and GPU you're recommending the cheapest unit at the desired performance level. Does quality and reliability not factor into the equation at all? :heink: 

By the way, after rebates, the XFX I posted is only $5 more than the one you posted. Its reviews are clearly better, so if I end up going with a 7850, I'll probably go with that.


I don't trust rebates. Rosewill is Newegg's house brand. While their older PSU's are low quality, they have gotten to become better over the years. Powercolor is fine as far as I know. There's no "bad" GPU maker as far as I know.
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