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GPUs and PSUs: Please Stop the Overestimation

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January 29, 2008 6:01:08 PM

Hey all,
I am posting this due to what I call an exaggeration on behalf of a portion of the community concerning the PSUs required for certain GPUs. Just today I read a post where a kid who just bought a 8800 GTS 512MB was recommended to get at least a 600 watt PSU just to run it. LOL, this is hilarious to me. I am running an old 8800 GTS 640MB, which consumes MORE power than the new GTS, on a two year old Ultra PSU with 500 watts, and I have NEVER had a problem. Where do people get off saying that someone needs at least a 600 W PSU for a single GPU set up? It is not the watts we should be obsessing over, it is the amps. A lot of people with problems with regards to PSUs are more likely not providing enough amps on the 12v rail. Yes, a new PSU will solve this, but hundreds of more watts needed at the same time? Please. Let's try to be somewhat efficient, in that we buy what we need or will need in the future, not what we might ever possibly need. I know about future-proofing and wiggle room, but that does not mean we all need 1000 watt PSUs. Again, when you make recommendations for people, you are making it for what THEY need, not what YOU want. You want them to be safe with their purchase, but you want them to not spend too much either. Many people lack the knowledge, and overselling them is unfair.

My theory is most of these people making the recommendations are using Newegg's PSU calculator to figure out how many watts they need. Let me be frank, Newegg's PSU calculator is inaccurate, for a reason. They overestimate the watts to make sure people have a PSU way more powerful than what they need so that they do not have customers calling and complaining that their new PSUs are not up to the job. Hell, Newegg says I shouldn't even be able to run my computer with my PSU!! Wow, I wonder how it's been doing it for the past year.

Concerning the new 3870X2 from AMD, and posts with people asking if their 680 watt PSUs will be enough, please note that on the power consumption page, that wattage listed is for the ENTIRE SETUP. In the article itself, Toms recommends having a 450 watt PSU. Are people reading this article? 450 watts, not 650 or more. you only need more when you are looking to go SLI or Crossfire with your cards.

In closing, my advice to people looking to see what PSU they need for a GPU, or if theirs is enough, look around online. Make sure you have enough amps for the card, the recommendation should be there somewhere. Lastly, try some of the PSU calculators online, and not Newegg's. They're there for a reason. Please keep in mind that more often than not manufacturers overestimate the required watts to be safe. As for people giving advice, try to be reasonable about this and not make people buy way more than they need. Lastly, if you get a PSU that comes with your case, it will most likely be crap, that is the norm. You're better off to buy the two separate.

Here is one calculator I like due to how specific you can be with it:

http://www.extreme.outervision.com/psucalculatorlite.js...
January 29, 2008 6:36:53 PM

I agree...my setup below on my Antec Neo 550 works great:

Q6600 overclocked
2900 Pro x2 overclocked
2x147 SCSI 10k hard drives
2x150 SATA hard drives
DVD
19" screen
January 29, 2008 6:50:13 PM

Wiggle room, future proofing, overclocking, water cooling, extra case fans, e-peen. See? There are reasons.

Quote:
Yes, a new PSU will solve this, but hundreds of more watts needed at the same time? Please. Let's try to be somewhat energy efficient.
Wattage has nothing to do with energy efficiency. A 1000W PSU doesn't use more power than a 500W PSU on the same system. If you're worried about efficiency, then check for the "80+ certification" on the side of your PSU.
Related resources
January 29, 2008 7:01:30 PM

Yes, you can run a Q6600 OC'd and an 8800GTX on a Antec Earthwatts 380W (look it up). By why would you want to start of the PSU's life at 75% capacity (before capacitor aging sets in)?

And qwerty is right, a PSU never pulls more watts than the system consumes, SHEESH! :pt1cable:  :pfff: 
January 29, 2008 7:06:17 PM

I fixed that point, when I said efficiency I meant it from a consumer vantage point, not an energy point, I fixed the wording. Sorry about that.
a c 199 U Graphics card
a c 126 ) Power supply
January 29, 2008 7:22:04 PM

I don't think I've recommended great big honking PSUs, but I'm sure I've echoed the thoughts of many others in referring to the list at http://www.tomswiki.com/page/Tiered+PSU+Listings?t=anon to help select a quality PSU. When reading PSU reviews on Jonnyguru.com, I've noticed that cheap PSUs often can't produce anywhere near their claimed output without dying a spectacular death, but may run reasonably well at up to 50% load. So, when [vendor of your choice] says "buy a 700W PSU!!!!," what they probably should be saying is to buy a good, quality 350W unit; perhaps they don't sell those (like if they're on tier-5 of that list).
a c 130 U Graphics card
January 29, 2008 7:46:23 PM

The situation would all be a lot clearer if someone with some weight say a reputable well known reviewing site started putting some of said weight onto the companies to list a Watts and Amps required rating, Also the PSU info stickers could do with standardising as well some only list the Amps on the +12 rails and as some will know you cant just add two 19 Amp rails and say you have 38 Amps. Some power supplies have really given me the run around when trying to look up the available amps on the net.
Mactronix
January 29, 2008 8:02:39 PM

I definitely agree that when recommending a power supply, it should be more about quality than quantity. That is, a better quality PSU with maybe less amps than a lower quality PSU with higher amps. I also agree that standardizing could definitely help when reporting the stats of different PSUs. My point is that I think to be safe, and maybe not research it, some people just get overly powerful PSUs. My little Ultra, for example, is actually a good PSU for only about 70-80$ US when I bought it and only has 500 watts, but actually has 34 amps, if I remember correctly.

I guess I am saying people shouldn't be so cavalier about recommending power supplies, and should encourage more research than just buying more than you need.

a c 199 U Graphics card
a c 126 ) Power supply
January 29, 2008 8:07:20 PM

Sales droids are generally programmed to recommend higher-priced models with bigger margins.
a c 130 U Graphics card
January 29, 2008 8:14:34 PM


Its funny how these things come up i have actually just finished researching for a planned build in the next couple of months and have decided that a corsair VX450 will be perfect for what i want single rail with 33Amps will have no trouble powering a single 3780 with a wolfdale one harddrive one rom drive and a seperate burner, couple gig of ram and still room to upgrade if need be.
Mactronix
January 29, 2008 8:23:29 PM

True, but having a 10 megawatt PSU is just SOOOO cool... especially when you turn it on any all the lights in the city dim a little.
January 29, 2008 8:23:40 PM

Quote:
I am posting this due to what I call an exaggeration on behalf of a portion of the community concerning the PSUs required for certain GPUs. Just today I read a post where a kid who just bought a 8800 GTS 512MB was recommended to get at least a 600 watt PSU just to run it. LOL, this is hilarious to me. I am running an old 8800 GTS 640MB, which consumes MORE power than the new GTS, on a two year old Ultra PSU with 500 watts, and I have NEVER had a problem. Where do people get off saying that someone needs at least a 600 W PSU for a single GPU set up? It is not the watts we should be obsessing over, it is the amps. A lot of people with problems with regards to PSUs are more likely not providing enough amps on the 12v rail. Yes, a new PSU will solve this, but hundreds of more watts needed at the same time? Please. Let's try to be somewhat efficient, in that we buy what we need or will need in the future, not what we might ever possibly need. I know about future-proofing and wiggle room, but that does not mean we all need 1000 watt PSUs. Again, when you make recommendations for people, you are making it for what THEY need, not what YOU want. You want them to be safe with their purchase, but you want them to not spend too much either. Many people lack the knowledge, and overselling them is unfair.
I agree. You'll generally see a lot of new people (mainly in the homebuilt section) want to start a build with a 1KW PSU. It's huge overkill for a single-card setup, and most of the veteran members should pipe in and correct the user about using a PSU like that. Same goes for newbies suggesting large PSU's to first time builders. (I've seen people also recommend the older 640MB GTS of the new G92 version. This is when you have to intervene and correct them on the spot before the buyer makes a very poor decision.)

Just for the record. I ran a PD8xx, 3 HDD's, 2 opticals, and an 8800GTS 640MB on a 420W Raidmax PSU. :o 
January 29, 2008 8:27:29 PM

I am using Antec NeoHe 550 to drive the following parts:
P35 Motherboard
Q6600 stock voltage@3.0G
4x1GB DDR2@2.2V, 800Mhz
8800GTS 512MB(OC to 750 Core and 1100 memory)
2X150G Raptor 10000RPM
3X320G Seagte 7200.10
1x200G Maxtor 7200RPM
1XDVD-RW
3x120mm fan
Power meter only shows ~280~290W Maximum from wall outlet during full load. NeoHe 550's efficiency is around 80%~85%, which results in 230~250W for the system.
The eXtreme Power Supply Calculator indicates a 430W PS recommended for my system, way overestimated. I believe even a decent 380W PS (such as earthwatt 380) should be enough for my system.
January 30, 2008 12:44:00 AM

rgeist554 said:
I agree. You'll generally see a lot of new people (mainly in the homebuilt section) want to start a build with a 1KW PSU. It's huge overkill for a single-card setup, and most of the veteran members should pipe in and correct the user about using a PSU like that.

I think I've seen this happen more times than the situation that the OP suggests.

Nuub-ie: I think I'll get a PC P&C 1200W for my new build.
Most THG Forums Members: Get a Tier 1/2 400-500W PSU and you'll be fine. Your welcome.

Quote:
remember, whenever anything better comes out, older products deteriorate in performance

With PSUs this in indeed correct with the constant charge and discharge of the capacitors (capacitor aging), but you probably already knew that :kaola: . However, I totally understand what you're saying. I believe there is a concensus that using the same hardware to do the same tasks over time does become slower, until the hardware sinks into obsolescence without a change in system demand.
January 30, 2008 1:24:29 AM

Quote:
And qwerty is right, a PSU never pulls more watts than the system consumes, SHEESH!

Actually, it does.
I refer you to lashrimp's post:
Quote:
I am using Antec NeoHe 550 to drive the following parts:
P35 Motherboard
Q6600 stock voltage@3.0G
4x1GB DDR2@2.2V, 800Mhz
8800GTS 512MB(OC to 750 Core and 1100 memory)
2X150G Raptor 10000RPM
3X320G Seagte 7200.10
1x200G Maxtor 7200RPM
1XDVD-RW
3x120mm fan
Power meter only shows ~280~290W Maximum from wall outlet during full load. NeoHe 550's efficiency is around 80%~85%, which results in 230~250W for the system.
The eXtreme Power Supply Calculator indicates a 430W PS recommended for my system, way overestimated. I believe even a decent 380W PS (such as earthwatt 380) should be enough for my system.

The lost energy is converted to heat.
The higher the efficiency, the less power a power supply is going to use to run a computer.

As for the topic, I pretty much agree with what has been said. People have blown this PSU thing way out of proportion.

January 30, 2008 1:40:55 AM

Onus said:
Sales droids are generally programmed to recommend higher-priced models with bigger margins.


Exacto.

A lot of people just see a large wattage rating and bug out. You wouldn't buy a Corvette (high wattage) with a 4 cylinder and 8 track player (low quality/low amperage).
a b U Graphics card
a b ) Power supply
January 30, 2008 1:52:44 AM

While I do agree with all of you guys that amperage is more important that watts, but try explaining that to a newb. and they be looking at you if your not human.

It's like with graphic cards, they think the larger the memory it has the better it performs where in reality it's
the speed of the core and ram and how high wide the memory interface is that matters the most.
But with today's DX10 cards that changes a bit.
January 30, 2008 2:25:33 AM

bash007 said:
Quote:
And qwerty is right, a PSU never pulls more watts than the system consumes, SHEESH!

Actually, it does.

I know that, I guess I worded it poorly. I was just trying to say that a 1000W PSU doesn't always pull 1000W when it's on, the components attached to it will determine how much load will be on it.
January 30, 2008 3:48:10 AM

As others have mentioned, amps are the important thing. When i first purchased the powersupply in my computer (Silverstone OP1000) I had the intention of using it with a skulltrail build. Needless to say after I found out that is was going to mostly proprietary I decided against that. Eitherway I bought the silverstone for 3 reasons. 1. 80amps on a single rail. 2. EPS (Dual Socket) Support. 3. 2 8pin pcie connectors.
January 30, 2008 3:58:41 AM

mactronix said:
The situation would all be a lot clearer if someone with some weight say a reputable well known reviewing site started putting some of said weight onto the companies to list a Watts and Amps required rating, Also the PSU info stickers could do with standardising as well some only list the Amps on the +12 rails and as some will know you cant just add two 19 Amp rails and say you have 38 Amps. Some power supplies have really given me the run around when trying to look up the available amps on the net.
Mactronix

http://forums.guru3d.com/showthread.php?t=205763

http://www.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354

http://www.tomshardware.com/2007/08/21/energy-efficient...

http://www.xtremesystems.org/forums/showthread.php?t=10...

http://forums.extremeoverclocking.com/showthread.php?t=...
January 30, 2008 4:16:32 AM

this guy is a real piece of work that started this thread!

bottom line is the higher psu is far more efficient the sweet spot is usually 40-60% of the rating

so if you are running a 800w psu or 500w psu for 400w load the 800w psu will run much cooler, much longer and use less energy

your an idiot to give advise based on one pc - i build one a week or more - high end systems. your psu should be much bigger then the load for many reasons. the cost is small

i have a theory that since you had nothing to post you decided to tell your story of your 500 watt psu! big deal!

you can have 600w psu with no 12v load
or you can have a shuttle 400w psu run sli or crossfire

this thread is a disgrace!
January 30, 2008 4:18:02 AM

murphy82nd said:
Hey all,
I am posting this due to what I call an exaggeration on behalf of a portion of the community concerning the PSUs required for certain GPUs. Just today I read a post where a kid who just bought a 8800 GTS 512MB was recommended to get at least a 600 watt PSU just to run it.

My theory is most of these people making the recommendations are using Newegg's PSU calculator to figure out how many watts they need. Let me be frank, Newegg's PSU calculator is inaccurate, for a reason


this post really makes me mad! the author has no clue!

the kid bought the right psu - you idiot!

i order 50k from newegg a year and i never ever seen a psu estimator - keep in mind none of the posts are a reference too me but you have no clue what you are talking about. the right psu about trial error, its about planning and its about upgradin but most of all its about the effecincy sweet spot vs cost - see below:



these psu are 1000w plus psu's - look where the effiecy is! yes its way down at 500-600w's the

your 500w psu is very ineffecient for your set up!
January 30, 2008 4:32:32 AM

dude you have no clue - what about sound level? your 500w psu is probably very loud - properly sizing a psu is important for size.

what about when its 90f outside? that 500w psu will over heat



again - larger psu's are much quieter
January 30, 2008 5:36:04 AM

I've actually personally built over a dozen PCs for personal use, so no I am not an idiot. My point was that most of these people do not need to upgrade their PSUs to get a new card, as many of them are fine, the wattage estimates are out of wack. There's no need to be rude, it just makes me ignore your post as a flamer. Be reasonable and I will listen.

As for efficiency, I know about that too my friend. At 300 watt load my PSU has an efficiency rating of 78%, at a full 500 watt load 73%, and I am probably not even over 350 watts as it is. Wow, that efficiency drop is probably gonna kill me. If you had read the whole post, you would see that most setups right now prob don't use more than 400 watts for single card solutions as it is. This was my point, they don't need 1000 watt PSUs, as the efficiency loss compared to say a 500 or 600 will not be that significant, however the cost will.

As for heat, I have never had a problem. In the summer my room is probably about 95 without AC and so was my dorm room, yet I had no problems. As for noise, I can't even tell when it's on, certainly not over the CPU fan, much less the case fans.

Personal attacks get you no where. I can defend my position just fine, if you wanted to talk about efficiency, that should have been your post, not these insults. Your conduct, not my post, is insulting.

Note: As a statistics major I find your graphs amusing. With the scales as they are they make tiny differences seem enormous. Congrats on manipulating the data.
January 30, 2008 5:59:26 AM

To the OP'er
1.You made some very valid points
2. You state in your reply:
"There's no need to be rude, it just makes me ignore your post as a flamer."
My question is who lit the match?
All anyone can do here is give advice, if it is taken so be it, if not at least other viewpoints are given.

"Note: As a statistics major I find your graphs amusing. With the scales as they are they make tiny differences seem enormous. Congrats on manipulating the data."

This contributed what (besides kindling for the fire) to this thread?
a b U Graphics card
January 30, 2008 6:21:56 AM

Points made, points replied.

Closed, move on. :hello: 
!