why get a psu with super high wattage?

L

LaserSamuraiHead

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Joined
Jun 19, 2003
Messages
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I've been reading around the forums for awhile, and i've been checking out those psu calculators that IceCzar has put up, and I keep noticing that for a system that equals something roughly like this:

Athlon 64 3200+
Geforce 6600 GT (i'm guessing the wattage on this one, and said it might be equivelant to a 5900)
Mobo that supports the a64
2 80 gig Seagate Hard drives (non-sata)
1 gig of PC3200 Ram
4 80mm case fans
1 Card reader
Cold Cathode
Keyboard/mouse + random USB devices i hook up occasionally
1 DVD burner

That i'll only need a power supply that roughly outputs 330 - 350 watts. I know i'll need one that outputs more amps on the 12V line due to the setup that I'll have, but as long as i get a 350 - 400 watt PSU from a reliable manufacturer with a decent amount of amps where they are needed, i should be ok. I notice that a lot of power supplies have 450+ watts, and that a lot of people here use them, and i'm wondering why. I find it hard to believe that most of the people here are running dual processors and huge raid arrays that would necessitate having a powerful PSU. And even figuring in expansion and a bit of future proofing, most people wouldn't need more than 400 watts. I was looking at getting a neopower but i'm not sure if i can justify the cost beyond having the modular design. Is there something I'm missing?
 
Yes

You forget that most people are much less informed than yourself! They see bigger wattage, ignoring everything else, and say it's better. Simple as that
 
haha, yeah, as i was walking to another building i realized i forgot to put the dvd burner i am using in the list. When i went to those calculator sites though, i put those in and still came up with a figure of around 330 Watts. As i was walking i also realized that if you are going to be overclocking you'll need more more wattage (and i overclock my systems) but how much extra wattage could that eat up? I can't imagine that a chip whose output is 90 watts could suddenly eat up 180 watts when overclocked, although i could be very, very wrong.
 
you're not that far off. My old 3.0c ate up around 90 watts stock but when overclocked to 4ghz and 1.75v day to day or 1.8v for suicide screenies, it ate up around 157-160 watts according to sandra (wattage measurement is one of the few things that sandra doesn't fudge from experience).

Plus, a video card such as the 6800 ultra OC WB edition (470mhz stock) which i will be getting eats up well over 100 watts. Add a volt mod and overclocking to that and you have another 150. Add a gig of ram running 500mhz 2-2-2-5, another volt mod, 3.5v to the memory and you have some more wattage. Plus a wd raptor and 2 160gb 7200rpm maxtors in raid, a dvd rom, super high speed cd rom, and a cd burner. Plus the mobo (another volt mod) and pci slots. Plus fans, water pumps, 4 cold cathodes, some LED's, radiator fans, etc.

You can see why I bought the pc power and cooling 510 deluxe.
 
LaserSamuraiHead said:
Is there something I'm missing?
Click to expand...
The mystery revolving around future power requirements. They tend to remain a mystery till the actual product ships.

Imagine just this one example in the near future.

SLI with dual video cards then throwing them into a typical gamer setup:

- Dual Video cards ala SLI
- Oc'd cpu
- 1/2 dozen fans
- 2-3 10,000rpm sata drives
- 2 optical drives
- usual assortment of pci cards
- you got the idea

How will the load be stably split? Will we need 3 +12v rails? How does the typical builder plan for such uncertainties? Sometimes they "overbuy" to hold out the possibility of using their psu's in future rigs. Imho the future looks pretty bleak for many 350-400w psu's currently available. Spending few extra dollars now 'might' save you from buying another psu in the near future (i stress "might" because the issue is a bit more complex than just raw power). This why i've lately been recommending the 550w fortron to people who inquire; high quality, heavy duty, inexpensive but i'll admit im not sure how future-proof it really is ;)

Edit: Here's a fellow pondering a similar question: http://www.hardforum.com/showthread.php?t=796410
 
LaserSamuraiHead said:
I've been reading around the forums for awhile, and i've been checking out those psu calculators that IceCzar has put up, and I keep noticing that for a system that equals something roughly like this:

Athlon 64 3200+
Geforce 6600 GT (i'm guessing the wattage on this one, and said it might be equivelant to a 5900)
Mobo that supports the a64
2 80 gig Seagate Hard drives (non-sata)
1 gig of PC3200 Ram
4 80mm case fans
1 Card reader
Cold Cathode
Keyboard/mouse + random USB devices i hook up occasionally
1 DVD burner

That i'll only need a power supply that roughly outputs 330 - 350 watts. I know i'll need one that outputs more amps on the 12V line due to the setup that I'll have, but as long as i get a 350 - 400 watt PSU from a reliable manufacturer with a decent amount of amps where they are needed, i should be ok. I notice that a lot of power supplies have 450+ watts, and that a lot of people here use them, and i'm wondering why. I find it hard to believe that most of the people here are running dual processors and huge raid arrays that would necessitate having a powerful PSU. And even figuring in expansion and a bit of future proofing, most people wouldn't need more than 400 watts. I was looking at getting a neopower but i'm not sure if i can justify the cost beyond having the modular design. Is there something I'm missing?
Click to expand...


Yes and I humble ly recommend the Turbo 425 deluxe from PC P &C ......Flawless
 
The fans are simple, run most of them from separate PSU. Only my Processor fan is running from the MB/PSU, all other I used an old PSU to run them...Why will I bother my PSU with fans..
 
Moto Guzzi said:
The fans are simple, run most of them from separate PSU. Only my Processor fan is running from the MB/PSU, all other I used an old PSU to run them...Why will I bother my PSU with fans..
Click to expand...
:rolleyes: When are people going to learn that running fans/lights from a seperate PSU is a waste?! The draw of an average 80mm would be ~0.1a or 1.2w. The draw from an average IDE hard drive is at least 0.5a @ 5v, 1a @ 12v, or 2.5w + 12w. And you're worried about running fans off of a seperate supply? Get real
And sorry if it sounds like i'm ranting at you, i'm not really, just at the whole "dual PSU for lights and toys" trend
 
Vertigo Acid said:
:rolleyes: When are people going to learn that running fans/lights from a seperate PSU is a waste?! The draw of an average 80mm would be ~0.1a or 1.2w. The draw from an average IDE hard drive is at least 0.5a @ 5v, 1a @ 12v, or 2.5w + 12w. And you're worried about running fans off of a seperate supply? Get real
And sorry if it sounds like i'm ranting at you, i'm not really, just at the whole "dual PSU for lights and toys" trend
Click to expand...

My 21watt cpu fan alone eats up my 12v rail :p :D ;)

It could be justified in some cases, but meh.

whats with the comparison with the hard drive? half a dozen differnt fans can draw the same, maby not just 1 80mm though.
 
21watt CPU fan? 21watt on the +12v = 1.75a... not even 92mm tornados draw that much. What fan are you using? My point with the comparison to the hard drive is that 99% of the modders out there will run all their fans and lights off a seperate power supply, but not any hard drives. 1 hard drive on a seperate PSU is going to have more effect than 10 fans, that's my point
 
LaserSamuraiHead said:
That i'll only need a power supply that roughly outputs 330 - 350 watts.
Click to expand...

very true, if
1.the supply was rated at the temperature your going to operate at
(Alaska, Siberia or South Dakota in Winter :p ) otherwise deduct a third off the amps rating

2. The manufacturer didnt lie, and say the rating is good when a fuse blows as opposed to when the rail dropped below the 5% varience spec

3. the current is realistically distributed to the rails where you need it
if its a 450 watt with only 18A on the +12V .....
your actually unable to use the majority of that power if your config needs it on the +12V

4. A PSU running at half its capacity will:
A. last longer
B. be cooler
C. deal with AC varience and internally dynamic load regulation better than one loaded right up next to its capacity

thus when taking about the "average" PSU for the "average" computer config
the wattage overall has increased,
alot of that can be attributed to the assorted above points, because not all PSU are created equal,
hense my sticky, Whats dont mean Jack :p


however, <peaks under the hood> yup 2 processors and a large RAID array :p
 
Ice Czar said:
however, <peaks under the hood> yup 2 processors and a large RAID array :p
Click to expand...


lucky! yeah, i read that thread about the temps affecting the psu, and that's a very good call. I'm almost positive im' going to get the neopower now, i was just wondering if i was falling into a hype trap and wasting money for no reason. I think that happens to a lot of people when they buy computer stuff, so i wanted to take a step back and rethink my buying process. Thanks for the help guys
 
well that certainly applies to PSU, but the "trap" is the bells and whistles
(finish, LED fans, cool wiring harnesses ect)

Three most important specs to look at are
1. amps per rail (and dual +12V rails for the highend and future) ignoring watts, and that they are where you need them for a specific config

2. the transient response also listed as the indvidual rail regulation (the smaller the percentage the better) standard is 5%, some will do 3% (Antec) 1% is very good (PCP&C)

4. The AC Ripple also listed as noise actually it Periodic and Random Deviation (PARD) on the DC line from the AC, and its measured in mV again the less the better
 
Vertigo Acid said:
:rolleyes: When are people going to learn that running fans/lights from a seperate PSU is a waste?! The draw of an average 80mm would be ~0.1a or 1.2w. The draw from an average IDE hard drive is at least 0.5a @ 5v, 1a @ 12v, or 2.5w + 12w. And you're worried about running fans off of a seperate supply? Get real
And sorry if it sounds like i'm ranting at you, i'm not really, just at the whole "dual PSU for lights and toys" trend
Click to expand...

i'm not so certain about that. the one time i can see that it would matter would be on boot. let me elaborate:

I had a cruddy 400W generic power supply which wasn't going to cut it for my new rig. I had no idea about PSU's (this was like 1 month ago), so I bought a 600W piece pf trash for $40. After it died (in all of about 3 days), I put in my old one 400W while waiting for the new one to arrive.

Using this older PSU, whenever I booted all of my fans/HHD's would spin up for about 0.5s, then the comp would reboot. They would spin up a touch more for the next 0.5s, then reboot. Repeat this for about 4-5 times total. When I opened my case wide and used a desk fan for case cooling and unplugged 4 of the 5 fans, it no longer rebooted on boot. So there's one situation (the one described) why it might actually make a small amount of sense to run the dual PSU. If you've got a lot of fans, a PSU on the edge might not get all it needs to get those fans up to 2000rpm.

Of course, that's only really an issue if you've got such a crappy PSU as I had.

Now, when I got to work this morning, I got an e-mail telling me my PCP+C 510W deluxe had been delivered at 9:38 this morning :D
 
When are people going to learn that running fans/lights from a seperate PSU is a waste?! The draw of an average 80mm would be ~0.1a or 1.2w. The draw from an average IDE hard drive is at least 0.5a @ 5v, 1a @ 12v, or 2.5w + 12w. And you're worried about running fans off of a seperate supply? Get real
Click to expand...

Sorry pal to burst your bubble, but my circuimstances are probably completely different than yours. In the 1st place my PC is build into a desk. I used and placed 8x sensors in stategic places to determine how my mods work. I did not suck cooling results out of thumb. I got 19x fans running and the intakes are filtred, forcing you to use more fans for proper airflow. These tempgauses don't lie, and I can immediately see if a mod worked overall or not. My next PC I will do the exact same method...No regrets after more than 3 years. I don't use SW to monitor temps!

The PSU on my PC feeds only the P4 fan and the GPU original fan. I did not see fit to connect all these fans on PC PSU. I cool everything with air, not just a Processor....... :D
 
Moto Guzzi said:
Sorry pal to burst your bubble, but my circuimstances are probably completely different than yours. In the 1st place my PC is build into a desk. I used and placed 8x sensors in stategic places to determine how my mods work. I did not suck cooling results out of thumb. I got 19x fans running and the intakes are filtred, forcing you to use more fans for proper airflow. These tempgauses don't lie, and I can immediately see if a mod worked overall or not. My next PC I will do the exact same method...No regrets after more than 3 years. I don't use SW to monitor temps!

The PSU on my PC feeds only the P4 fan and the GPU original fan. I did not see fit to connect all these fans on PC PSU. I cool everything with air, not just a Processor....... :D
Click to expand...

That's awesome. Did you put mounting stuff into the desk to hold the parts, or did you build a desk around a case frame?

Edit: and "tempgauses" sounds like some uber-futuristic heating/cooling system based around magnetic polarity :)
 
I bought myself a 600W PSU simply because I plan to never get rid of it. :D
 
I bought the largest solid wooden desk I could find, then chucked out the righthand side drawers, making a filipping door out of it witch can be easily removed to get PC out. The outer side of the PC is sealed off around the centre inside the desk to force cool air from front via filters only one way through....No such thing as warm air pockets hanging around.

If you hold your hand in front of the PC, there is a solid sucktion inwards.

I cooled everything, and I mean everything, like all the transformers for USB stuff etc. They are all in the back, with a 220V fan at rear to keep the direction of overall airflow just in and just out...one way only. The cables are all neatly grouped toghether ending on diff heights on a pole, making it easy to find all the connections to replug if PC has to be taken out.

Out of experience I know for a fact that PC parts last very long if everything is cooled around 21c, hardware hardly ever packs up.., thats why I did this.
 
Ice Czar said:
well that certainly applies to PSU, but the "trap" is the bells and whistles
(finish, LED fans, cool wiring harnesses ect)

Three most important specs to look at are
1. amps per rail (and dual +12V rails for the highend and future) ignoring watts, and that they are where you need them for a specific config

2. the transient response also listed as the indvidual rail regulation (the smaller the percentage the better) standard is 5%, some will do 3% (Antec) 1% is very good (PCP&C)

4. The AC Ripple also listed as noise actually it Periodic and Random Deviation (PARD) on the DC line from the AC, and its measured in mV again the less the better
Click to expand...

Agreed. A good psu manufacturer means a lot more than the wattage rating. The rig in my sig runs an oc'ed p4 @ 3.06, a 6800GT at stock (for now), 4 HD's, 6 case fans and 2 dvd drives. Not bad for a 430W, but it's an enermax. For that reason alone I stuck with enermax on my new build, jumping to a 480W with dual 12V rails. Personally I didn't see the point in paying twice the price for an extra 70-120W that I most likely wouldn't come close to using.
 
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