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How much Wattage of PSU Power do I Need?

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February 4, 2010 6:44:09 PM

Hi, I only just wanna ask about how much wattage of PSU power do I need for this spec:

Motherboard: ASUS P7P55D-E PRO (mainstream motherboard)
CPU: Intel Core i7 860 (high-end mainstream CPU)
CPU Cooler: Thermalright Venomous X
RAM Memory: 4GB DDR3 Ram
Hard disk: Seagate SATA III HDD
PC Case: Thermaltake Armor + (with 6 fans)
Single Video Card: ATI Radeon HD 5870 (or possibly Radeon HD 5890 in the future)
Sound Card: Creative Sound Blaster X-Fi Fatality Pro
Speakers: Creative Gigaworks 550W
number of USB devices: about 3 or 4



I am currently interested with Enermax brand PSUs with 80+ Gold Energy Efficient Certified.

I was looking at something like Enermax Modu 87+ (500W/600W/800W)...

Many PSU Calculators said that I need about 350 Watts of PSU Power to get this system spec running but how much I can trust these PSU Calculators??? Are these PSU Calculators' results accurate or at least close to the correct results? :??: 

I used Enermax PSU Calculator Outervision and it said something like about 347W of power to run this spec I posted.

Should I go with a 500W PSU? Or should I go with something like 800W PSU or more? :??: 

PS: I might do Crossfire or SLI in the future so I think that it is better for me to get a PSU with a little bit more of extra Wattage of Power to be more sure/safer.

More about : wattage psu power

February 4, 2010 6:59:10 PM

jonpaul37 said:
The PSU is the most important piece of hardware you have in a PC, i would go with a reputable brand like OCZ or Corsair, anything over 650w from those 2 brands will suffice, my recommendation is below:

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


So 650W PSU is enough for my spec that I posted?

hmmm.... but that Corsair PSU isn't the most energy efficient PSU because it does not have 80+ Gold Certificate....

I found out recently that now the PSU makers are going for 80+ Gold PSUs and 80+ Gold sticker is becoming marketing key for customers.

For example, OCZ came up with the Z series with 80+ Gold (Z1000 PSU) and then Enermax replied with EG1100 and Modu 87+ and Pro 87+.

http://www.techpowerup.com/90013/OCZ_Achieves_80_Plus_G...

http://www.enermax.co.uk/index.php?L=2&id=17
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February 4, 2010 7:06:41 PM

Is Enermax of Taiwan a good brand for PSU???

Enermax Modu 87+

(500W/600W/700W/800W Models available)

Enermax Pro 87+

(500W/600W Models available)

OCZ Z1000

(1000W Model)

Seasonic X series





So should I go with 600W PSU or 650W PSU or 700W PSU or 800W PSU or 850W PSU??

2 people here mentioned about 650W PSU and 1 person mentioned about 850W PSU. So I'm a bit confuse... :pt1cable: 
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a b ) Power supply
February 4, 2010 7:09:31 PM

Yes they are good, a bit pricey but well worth it.
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a b ) Power supply
February 4, 2010 7:20:56 PM

OP said "ATI Radeon HD 5870 (or possibly Radeon HD 5890 in the future)" this is why i am justifying the 650w PSU or better...
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a b ) Power supply
February 4, 2010 7:25:14 PM

650 and above, don't settle for anything less....
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February 4, 2010 7:30:59 PM

Alright, so I should not go below the 650W. 650W is the minimum I could get and save more money.

Well, it is also possible that Radeon HD 5890 would consume lesser power than Radeon HD 5870 especially if it is running on 32nm GPU...

Anyway, I think that I will go with something like Enermax Modu 87+ with 700W of Power. The new Enermax Modu 87+ and Pro 87+ Models will be release soon in the early 2010 (possibly by next month) and this is why I am interested in these new 80+ Gold Highly Energy Efficient PSU which could save me more money on electric bills after each month as well as saving the environment... Green computing is good. :D 

Looks like we cannot anymore trust the PSU calculators on internet. PSU calculators sucks. :pfff: 
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a b ) Power supply
February 4, 2010 7:37:12 PM

The PSU calculator gives you an estimate of how much power the PSU needs to continuously supply. Of course, you probably didn't change the system utilization option. I'm sure if you would have selected 100% you would have gotten a higher number. To give you an example when playing a game my system uses around 280W (a little more playing Crysis). When I stress it using Furmark and Prime 95 on 3 cores (furmark needs one), that number jumps over 400W. Of course some of that power isn't supplied to the system, but rather transferred to heat in the PSU (no PSU is 100% efficient, but mines over 80 under load :D ).

Anyway, I say go with a good 600W PSU. If you want to crossfire in the future then go with something better like 800W +. I should point out that the less a PSU is stressed, the longer it generally lasts. In otherwords, in a system that uses 400W a PSU rated for 600W will generally last longer than one only rated for 450W.
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a c 248 ) Power supply
February 4, 2010 7:37:14 PM

Here are the official power requirements for the ATI Radeon HD 5870 video card.

ATI Radeon™ HD5870 System Requirements:

PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard.

500 Watt or greater power supply with two, 75 watt, 6-pin, PCI Express® power connectors.

600 Watt or greater power supply with four, 75 watt, 6-pin, PCI Express® connectors for ATI CrossFireX™ technology in dual mode.

The power supply recommendations are for an entire pc system.



Here are the official power requirements for the ATI Radeon™ HD 5970 video card.


ATI Radeon™ HD5970 System Requirements:

PCI Express® based PC is required with one X16 lane graphics slot available on the motherboard

650 Watt or greater power supply with one 75 watt, 6-pin and one 150 watt, 8-pin PCI Express® power connectors

850 Watt power supply with two 75 watt 6-pin, and two 150 watt, 8-pin, PCI Express connectors for ATI CrossFireX™ technology in dual mode


The power supply recommendations are for an entire pc system.


There are no power requirements for a HD Radeon 5890 video card because it is not available.
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a b ) Power supply
February 4, 2010 7:49:44 PM

Techno-boy said:

Looks like we cannot anymore trust the PSU calculators on internet. PSU calculators sucks. :pfff: 


Well they tell you how much approx is needed then you have to consider when buying a PSU they are not 100% efficient and you do not want to run them at or near their Max output and also consider that as they age the output level somewhat decreases so for best results get something around twice what is suggested (by most accounts the sweet spot for performance efficiency on a PSU is around the 50% load mark) by the calculator (ie. in your case of 350W usage you'll want somewhere in the neighborhood of 700Watts give or take ( a bit less if you are sticking to high quality manufacturers and 80+ efficiency certified units) so a 650+ PSU made by a quality company should be sufficient to last the lifettime of your system.
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February 4, 2010 8:02:51 PM

megamanx00 said:
The PSU calculator gives you an estimate of how much power the PSU needs to continuously supply. Of course, you probably didn't change the system utilization option. I'm sure if you would have selected 100% you would have gotten a higher number. To give you an example when playing a game my system uses around 280W (a little more playing Crysis). When I stress it using Furmark and Prime 95 on 3 cores (furmark needs one), that number jumps over 400W. Of course some of that power isn't supplied to the system, but rather transferred to heat in the PSU (no PSU is 100% efficient, but mines over 80 under load :D ).

Anyway, I say go with a good 600W PSU. If you want to crossfire in the future then go with something better like 800W +. I should point out that the less a PSU is stressed, the longer it generally lasts. In otherwords, in a system that uses 400W a PSU rated for 600W will generally last longer than one only rated for 450W.


Thanks for reminding me about the 100% full load because indeed, I did not put the option as 100% full load since the option said that it is not recommended so I went with default which was lower than 100%. You are right, when the system is idle, it would consume lesser power unless if it is running at 100% full load. Now I will go back and re-try the Enermax PSU Calculator again but this time with 100% full load for the system utilization option and I hope that I would get a better or more realistic result.

You are also right about buying a more powerful PSU with extra watts because using the PSU at its full/maximum capacity can reduce its lifespan and then risk to be ruined.

So you think that 800W PSU would be the best spot for crossfire/sli and 600W is good for single video card?

Anyway, I think that 700W is enough for this system spec with 2 Radeon HD 5870. Assuming that the system would use 600W from a 700W PSU, this would leave the extra 100W untouch and prolonging the lifespan of the PSU and it would cost lesser than a 800W PSU too so I might be going with Enermax Modu 87+ 700W PSU... Or should I really go with 800W PSU and leaving the extra 200W untouch? What do you guys think?

If nobody disagree with my conclusion then I shall leave this as a final decision: going with an Enermax Modu 87+ 700W PSU with 80+ Gold Energy Efficient Certified for the spec I posted above...

Sorry if I was being a bit noob with PSUs. :D 
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a b ) Power supply
February 5, 2010 11:26:51 AM

400w PSU from corsair or OCZ for single video card
650w PSU from corsair or OCZ for dual video card

no need for anything more if you get either of those brands, period.

Also, i'm not sure if Enermax is a good quality PSU company, choose well because if you buy a bad quality PSU, you could risk every piece of hardware in your PC.
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a b ) Power supply
February 5, 2010 2:10:47 PM

Enermax PSU's are TOP-NOTCH, they are as GOOD as any Corsair series, they only drawback is that the warranty is not as great as Corsair , ENERMAX only gives you 3 years, the Corsair TX series gives you 5 years and the HX series gives you 7 years =)
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a b ) Power supply
February 5, 2010 2:30:07 PM

Thanks OvrClkr, i was not aware of that, adding Enermax to my list of Quality PSU's
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a b ) Power supply
February 5, 2010 2:44:52 PM

Just making sure anyone who is looking to buy a PSU gets what they paid for =) , personally I would not settle for anything less than 5 years.

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a b ) Power supply
February 5, 2010 2:56:42 PM

OvrClkr said:
Just making sure anyone who is looking to buy a PSU gets what they paid for =) , personally I would not settle for anything less than 5 years.


I agree, i have a PC power & cooling PSU rigtht now, but have a Corsair that i have not used yet.

that's what i love about PSU's, not much will change within 5 years if you have a decent one to begin with...
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a b ) Power supply
February 5, 2010 3:23:31 PM

Yea the PC power & cooling PSU's are among the best, VERY reliable and they last forever....
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February 5, 2010 3:39:20 PM

OvrClkr said:
Enermax PSU's are TOP-NOTCH, they are as GOOD as any Corsair series, they only drawback is that the warranty is not as great as Corsair , ENERMAX only gives you 3 years, the Corsair TX series gives you 5 years and the HX series gives you 7 years =)


Actually, Enermax also offer 5 years of warranty and it says on their website:



(5 years warranty for their new 80+ Gold PSUs)

I also changed the system utilization option to 100% full load on the PSU calculator and this time I got about 450W of Power Requirement as a result for the current spec that I posted... Also, if I still wanna stick with Enermax Modu 97+ series then the best choice to go with is definitely 700W model because the 650W model and 750W model are not available for the moment and the 800W might be a little bit overkill and it will be release much later so there will only be 500W/600W/700W models by this mid February and then about after 1 month later, there will be 800W model.

Even if it cost a little bit more, I would not mind much because seriously, how many times do we buy PSU? We buy a PSU like in every 5-8 years or more so it is better to spend a bit more and get a good quality PSU so it would last longer and save our money more. Also, getting 80+ Gold PSUs or the most energy efficient PSU, would save our money on electric bills in 5-8 years of usage so that is why I was looking at only 80+ Gold certified PSUs. 80+ Gold sticker is also becoming a marketing key that many costumers are looking for when buying PSU. Today, many PSU makers are trying to hit over 90% of energy efficiency and breaking the world's record which is something very difficult to do in the past 3 years until now, it is becoming reality. Using clean energy and doing green computing are the future way which will also save our environment and avoid global warming. :D 

Now, I started to sound like one of those marketing advertisers and environment conservationists. Lol! :D 
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a b ) Power supply
February 5, 2010 4:30:49 PM

Correct but the 87+ line (GALAXY and REVOLUTION) is going to cost you for that extra 2 years of warranty. The HX series is just as powerfull and costs less + better warranty. It all cames doen to how much you are willing to spend =)
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a c 248 ) Power supply
February 6, 2010 1:04:03 AM

Techno-boy - The newer Enermax Gold Modu 87+ 700 watt power supply is a very good power supply.

Here are a few links to technical reviews:

http://www.jonnyguru.com/modules.php?name=NDReviews&op=...

http://www.anandtech.com/casecoolingpsus/showdoc.aspx?i...

http://www.hardwaresecrets.com/article/900

There is something I need to point out. Enermax and OCZ are inconsistent. Both companies offer some very good power supplies. There is no doubt about that. However, they also have low budget, low quality models of questionable performance and value. It is not fair to give them a blanket endorsement. Other people may read the posts and incorrectly assume that all OCZ and Enermax power supplies are high quality units. That simply is not the case. The quality and performance varies. It would be a disservice to individuals who read these threads. A misinformed individual might purchase a low budget, low quality model thinking it was a high quality unit. OCZ and Enermax are not alone. In the general psu rule of thumb I developed last year I mention Antec as one example. The Antec Earthwatts series is vastly superior to the older Basiq series. There is no doubt about that.

OvrClkr - Corsair currently has two Gold certified power supplies - the HX750 and the HX850. They are modular psu's that come with a 7 year warranty. They may or may not be a better value than the Enermax Modu87+. It is a matter of determining who has the better price at any given time. Personally I splurged and got the Seasonic X-650 Gold.

Currently newegg.com offers 9 Gold Certified power supplies. For the moment the Seasonic X 650 Gold appears to be the best value:

http://www.newegg.com/Product/ProductList.aspx?Submit=E...






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February 6, 2010 2:55:36 PM

From what I read on some articles is that Seasonic X series would save more energy only on full load but Enermax Modu 87+ would save more energy on middle load and idle.

I think that Antec, Corsair, OCZ, Seasonic X series' value on Newegg (service for only North American customers) are better for someone who is living in North America since they are American local products (Seasonic is an American company like OCZ and others).

Thermaltake/Coolermaster/Lian Li/ASUS/Enermax's value would be better for those living in Asia since Enermax is a Taiwanese company unless if they also open a facility in other continents like America/Europe.

Foreign products that comes from far away tends to cost more because they got to pay for shipping and handling and tax so it is normal for people on Newegg to buy something like Antec products/Corsair/Seasonic and their price would normally be much lower. However, I don't live in North America and I am going to buy these PC components when I go to Asia.

Anyway, thanks for those interesting articles, JohnnyLucky.
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a c 144 ) Power supply
February 6, 2010 4:20:17 PM

Actually, most of them are made in Asia. U.S. labor is just too expensive.
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a c 248 ) Power supply
February 6, 2010 5:00:49 PM

Techno-boy - I read that in the summary page of the Hardware Secrets review that I linked to. Here is a direct quote from Hardware Secrets:

"Compared to the other 80 Plus Gold that we’ve already reviewed, Seasonic X-Series 650 W, this new unit from Enermax achieved a little bit better efficiency under light load, while this model from Seasonic achieved a little bit better efficiency under full load."

Unfortunately they didn't provide any additional explanation in the summary so I had to go to the Hardware Secrets test results for each psu to see what they meant.

At 21.5% load the Enermax was determined to be operating at 90.0% efficiency.

At 21.8% load the Seasonic was determined to be operating at 88.3% efficiency.

At 100.7% load the Enermax was determined to be operating at 86.1% efficiency.

At 102.0% load the Seasonic was determined to be operating at 87.7% efficiency.

At the low end there is a 1.7% difference in efficiency. At the high end there is a 1.6% difference. I have no idea how to convert those specific results into dollars and cents on an electric bill for the typical user, the enthusiast, or the hardcore gamer.

I got curious and went over to jonnyguru.com for another look at their test results. Their results were a bit different.

At 20% load the Enermax was determined to be operating at 90.4% efficiency.

At 20% load the Seasonic was determined to be operating at 90.5% efficiency.

At 100% load the Enermax was determined to be operating at 87.2% efificency.

At 100% load the Seasonic was determined to be operating at 89.3% efficiency.

It is apparent that test results vary. That is to be expected. Perhaps one should look at the overall performance of both units. In that respect, jonnyguru.com provided significantly more information. The site tested the Seasonic and OCZ psu's before the Enermax unit. There were some comparisons and comments about that in the Enermax review:

http://www.jonnyguru.com/modules.php?name=NDReviews&op=...

Seasonic is not an American company. Seasonic is a Taiwanese company. Headquarters are located in Shih-Lin, Taipei, Taiwan. The original factory is in Taiwan. A second factory is located in Dong Guan, China. Seasonic has a regional office in the USA and in the Netherlands to serve the North American and European markets.





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February 6, 2010 7:27:59 PM

JohnnyLucky said:
Techno-boy - I read that in the summary page of the Hardware Secrets review that I linked to. Here is a direct quote from Hardware Secrets:

"Compared to the other 80 Plus Gold that we’ve already reviewed, Seasonic X-Series 650 W, this new unit from Enermax achieved a little bit better efficiency under light load, while this model from Seasonic achieved a little bit better efficiency under full load."


That's exactly what I had read about 4 days ago but I did not remember the website precisely. Anyway, you got the article link. Thankyou. :) 

I think that saving energy while light load or being idle is better than during full load because normally our computers do not run at full load except for when we do gaming or heavy multiple tasks.

However, Seasonic's value is cheaper on Newegg but I don't know if it would be the same in other places since I'm not in North America.


JohnnyLucky said:
Seasonic is not an American company. Seasonic is a Taiwanese company. Headquarters are located in Shih-Lin, Taipei, Taiwan. The original factory is in Taiwan. A second factory is located in Dong Guan, China. Seasonic has a regional office in the USA and in the Netherlands to serve the North American and European markets.


Great! Now, I'm feeling more proud to be in Asia and acting like an Asian. :D 
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a c 248 ) Power supply
February 6, 2010 7:45:20 PM

Speaking of Asia - Enermax only makes about 50% of the power supplies they market. The other 50% are made by other manufacturers in Asia. It was the same way with PC Power and Cooling. Their Silencer models were probably the best power supplies they ever offered. They were manufactured by Seasonic for PC Power and Cooling. No wonder they were excellent psu's.

The Seasonic X-650 Gold and the Enermax Modu87+ are brand new designs with some new components. jonnyguru.com very briefly mentioned the new components were identical. I wonder if Seasonic makes the MODU87+ for Enermax? That would explain the almost identical performance and noise reduction.
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February 6, 2010 8:11:06 PM

JohnnyLucky said:
The Seasonic X-650 Gold and the Enermax Modu87+ are brand new designs with some new components. jonnyguru.com very briefly mentioned the new components were identical. I wonder if Seasonic makes the MODU87+ for Enermax? That would explain the almost identical performance and noise reduction.


But they are competitors/rivals, why would Seasonic offer a secret answer to Enermax about how to gain 80+ Gold of Energy Efficiency??? :ouch:  That would sound just like NVIDIA is giving secret PhysX codes to the rival ATI/AMD or Intel is helping AMD to make Phenom III or something. Lol! :D 

Both sides wanted to offer the best solution for 80+ Gold of energy effiency by hitting over 90% of energy efficiency so I don't think that both sides would be giving their secret solution to each other unless if someone is paying for it because their solution could be proprietary. Anyway, it is possible that the last company to make 80+ Gold PSUs could open the rivals' PSU and see inside of it to learn about how they were made.

I remember that one time, Enermax did showed an image of the inner part of their Revolution 85+ PSU (if I'm correct) with one section being censored. The section that was censored could possibly be the solution to archieve the 80+ Silver of Energy Efficiency and that is what Enermax does not want to show to its rivals. :o 
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February 7, 2010 8:58:18 PM

I've heard that PCP&C is actually owned by OCZ now, but still remains to be about the same quality as before, even though OCZ has released their own branded power supplies.

Price-point wise, Antec and Corsair seem to be real good, efficiency depends on who's design they use too.


Don't start with the cheaper in China propaganda. Labor wise it may be true, but unless you got someone standing over your Chinese "slave labor" demanding and enforcing QC, the defect rates go significantly up. the MBA types ignore this fact though and leave it in the warranty coverage costs. (I'm going to stop here as the discussion of this is OT in this specific forum.)
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a b ) Power supply
February 7, 2010 10:27:14 PM

personally I think OCZ sucks in General, I have had many customers complain about their ram and PSU's....
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February 7, 2010 11:46:04 PM

shrapnel_indie said:
I've heard that PCP&C is actually owned by OCZ now, but still remains to be about the same quality as before, even though OCZ has released their own branded power supplies.

Price-point wise, Antec and Corsair seem to be real good, efficiency depends on who's design they use too.


Don't start with the cheaper in China propaganda. Labor wise it may be true, but unless you got someone standing over your Chinese "slave labor" demanding and enforcing QC, the defect rates go significantly up. the MBA types ignore this fact though and leave it in the warranty coverage costs. (I'm going to stop here as the discussion of this is OT in this specific forum.)


Supporting the Chinese regime's cheaper products is as bad as supporting American Arrogant Imperialism. :ouch: 

Anyway, most high-tech products are not Chinese but they are Taiwanese products so there is no problem. :bounce: 

Look at wikipedia for company's profile information before you buy. Enermax is Taiwanese. I just hope that Enermax isn't hiring any Chinese slaves in China or something... :D 

Save Democratic Taiwan and its independence! :D 

Enough with Politics... :heink: 
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a c 248 ) Power supply
February 8, 2010 2:30:15 AM

OCZ did in fact acquire PC Power & Cooling. However, they operate as two separate companies. Neither one makes their own power supplies. Other companies make them. Both brands are inconsistent in their quality. PC Power & Cooling's Silencer series were the best power supplies they ever had. It's no wonder. The Silencer models were manufactured by Seasonic.
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