How much wattage do you need?

skurge13 · 11-04-2003, 05:45 PM

A friend is upgrading to a P4 3.0 computer and was asking me what he should get for a power supply. He said he talked to a computer tech who said for that he would need at least a 450 watt power supply.

Isn't that total overkill? From what I've read (here's a link: http://www.silentpcreview.com/module...rtid=28&page=1) the power draw of a computer, even at maximum load, doesn't exceed 100 watts and the whole "gotta get a bigger power supply" is just a marketing scheme to get people to buy more.

However, before I tell him this, I want to make SURE this is true. He currently has a 250 watt power supply. So will that be enough, or is the marketing hype for real?

**k0NG0** · 11-04-2003, 05:54 PM

Saying "at least 450W" is a stretch if you ask me. 400W should be more than enough for any worst-case scenario possible with a normally equipped computer.

SPCR uses a 1.6A Pentium 4 as a reference platform if I'm not mistaken, so the 100W figure should be using that CPU. It all depends on how many components you put into the computer.

400W should be OK for any normal PC today. I'd say 350W is enough too. There has been a power rating inflation in PSUs talked about in the last few years, something the PSU manufacturers will love and try to support as much they can, since they earn more money in the process.

-kONGO

skurge13 · 11-04-2003, 07:02 PM

What would happen if he didn't have enough power? What would the symptoms be? Would it cause any damage?

AGR964 · 11-04-2003, 07:10 PM

Usually more important than the wattage rating is the amperage rating for the individual voltages. All CPU's these days take their voltage from the 12v leg of the PSU. Make sure the power supply they get has at least 20A on the 12v leg, and you should be fine.

BBThumper · 11-04-2003, 07:14 PM

......no damage but it might not boot-random reboots-inability to overclock. PSU is one of the most overlooked parts in my opinion. A good PSU will even give you a faster better performing maching. Like "kONGO" said a name brand 400watt will work any pc today but if you are using alot of fans, any new video card, alot of H/D's then I would go higher. Even if you don't need it, its good to have...............I know alot of guys the only got a 400watt and it ran great until they put in a 9800pro

................

RACINGX · 11-04-2003, 07:26 PM

Antec Truepower 550w here have had it almost 2 years and no problems at all.

WarpSpeed · 11-04-2003, 07:45 PM

It's not simply a matter of total wattage or max amperage, but the stability of the PSU output is critical, especially if you are really pushing your components. A cheap 450 watt unit might perform much less well than a good quality 350 watt unit.

pointreyes · 11-04-2003, 11:49 PM

Quote:

Originally posted by WarpSpeed
It's not simply a matter of total wattage or max amperage, but the stability of the PSU output is critical, especially if you are really pushing your components. A cheap 450 watt unit might perform much less well than a good quality 350 watt unit.

Yep, that's pretty much the way I see it to. I will even be testing this in the next few days because I purchased the Antec LAN case which has the Antec 'blue-light' 350w PSU. I will be testing that PSU on my DFI LANParty 875 Pro (Canterwood board) which has a 2.6c oc'ed to 3.15Ghz using two sticks of OCZ4000, one hard drive, and the AIW 9600 Pro. I would expect that to be sufficient. On the same note, I had this past weekend the Antec 380w from the Sonata case to lose the 12v rail. I fortunately had a PSU that I was just getting ready to return to Best Buy (never used even) and viola system has been running great since. If it was not for the immediate need for a case with PSU I would probably go for this 400 ATX PSU though: http://www.pcpowerandcooling.com/pro...aquiet_atx.htm

BBThumper · 11-05-2003, 12:24 AM

........I have had alot of sucess with that 350w, saved me 3 times so far when a 400 and 2 450w PSU's just wouldn't boot a system ...........

pointreyes · 11-05-2003, 01:03 AM

Quote:

Originally posted by BBThumper
........I have had alot of sucess with that 350w, saved me 3 times so far when a 400 and 2 450w PSU's just wouldn't boot a system ...........

Well, you are getting to find this interesting. My DFI Canterwood board did not like the 380w and it did not like the 350w I just tried. Back to the 430w and viola works. The DFI would power up but the processor was dead until I used the 430w and then all is well. Strange.

8itgreat · 11-05-2003, 01:21 AM

i use an antec 350W Smart Power with no problems at all...i oc about 600mhz to 3ghz ....but my vid card is a geforce 4 Ti4200 128 mb....i know if i dropped a high end ATI in there i would be upgrading my psu for sure....not sure if i updated my specs here yet ....added an audigy 2, tv tuner card leadtek,,,,if its not there....and all is well with a bit of room to spare

BBThumper · 11-05-2003, 02:03 AM

.......its because its a DFI

...................

pointreyes · 11-05-2003, 11:36 AM

Quote:

Originally posted by BBThumper
.......its because its a DFI ...................

- it's power hungry.

Are DFI boards suckers of 12v lines?

Sierra_abx · 11-05-2003, 12:14 PM

Many PSU makers will use peak power ratings when marketing their power supplies. Under normal circumstances, you will never see peak power. So a PSU rated at 450W may actually be giving you only 350-400W. And as the temperature inside the case heats up, the amount of available power will go down, which is why good ventilation is a must.

Your friend's 250W PSU is probably not going to be enough. There is a lot of power-hungry equipment. Many P4 boards, for instance, require additional power through a ATX12V connector. It's worth the money, in my opinion, to buy a quality PSU because a bad or weak power supply can wreak havoc with your system.

skurge13 · 11-05-2003, 02:01 PM

Thanks for the awesome help, guys, and the advice on who the quality manufactureres are.

11-04-2003, 05:45 PM	#1
skurge13 Registered User Join Date: Nov 2003 Posts: 19	How much wattage do you need? A friend is upgrading to a P4 3.0 computer and was asking me what he should get for a power supply. He said he talked to a computer tech who said for that he would need at least a 450 watt power supply. Isn't that total overkill? From what I've read (here's a link: http://www.silentpcreview.com/module...rtid=28&page=1) the power draw of a computer, even at maximum load, doesn't exceed 100 watts and the whole "gotta get a bigger power supply" is just a marketing scheme to get people to buy more. However, before I tell him this, I want to make SURE this is true. He currently has a 250 watt power supply. So will that be enough, or is the marketing hype for real?
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11-04-2003, 05:54 PM	#2
k0NG0 Remembering TQ Join Date: Mar 2001 Location: Sweden Posts: 13,750	Saying "at least 450W" is a stretch if you ask me. 400W should be more than enough for any worst-case scenario possible with a normally equipped computer. SPCR uses a 1.6A Pentium 4 as a reference platform if I'm not mistaken, so the 100W figure should be using that CPU. It all depends on how many components you put into the computer. 400W should be OK for any normal PC today. I'd say 350W is enough too. There has been a power rating inflation in PSUs talked about in the last few years, something the PSU manufacturers will love and try to support as much they can, since they earn more money in the process. -kONGO __________________ Use Firefox - "the one that blocks all the schmutz" Feeling multicore elation? Remember this correlation: Amdahl's Law.
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11-04-2003, 07:02 PM	#3
skurge13 Registered User Join Date: Nov 2003 Posts: 19	What would happen if he didn't have enough power? What would the symptoms be? Would it cause any damage?
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11-04-2003, 07:10 PM	#4
AGR964 SeñorMushyBottom Join Date: Sep 2001 Location: Sunny California Posts: 2,129	Usually more important than the wattage rating is the amperage rating for the individual voltages. All CPU's these days take their voltage from the 12v leg of the PSU. Make sure the power supply they get has at least 20A on the 12v leg, and you should be fine. __________________ MSI K8N Neo2 Platinum; 939 A64 Winchester 2.3 GHz; Sapphire Radeon 9800 Pro; 74GB Raptor; Dual Channel Mushkin 1024MB 2-2-2-10 fjerbvpodjytgdkrfg
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11-04-2003, 07:14 PM	#5
BBThumper Happy, Joyous and Free Join Date: Jun 2003 Location: Philly Posts: 2,024	......no damage but it might not boot-random reboots-inability to overclock. PSU is one of the most overlooked parts in my opinion. A good PSU will even give you a faster better performing maching. Like "kONGO" said a name brand 400watt will work any pc today but if you are using alot of fans, any new video card, alot of H/D's then I would go higher. Even if you don't need it, its good to have...............I know alot of guys the only got a 400watt and it ran great until they put in a 9800pro ................ __________________ ASUS M3A32-MVP Deluxe AMD Phenom 9600 XP-90c w/ a T.T. 92mm fan 2 x 2gig pc26400 Nvidia 8400 2 x Raptors in Raid 0 ......My City's moto: Welcome to Philly, now get the heck out!!!!!!!
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11-04-2003, 07:26 PM	#6
RACINGX Hightech Redneck Join Date: Jun 2002 Location: Texas Posts: 411	Antec Truepower 550w here have had it almost 2 years and no problems at all. __________________ "There are no stupid questions just stupid people." ASUS A8V Rev 2 Bios 1009 AMD Athlon 64 3200+ Winchester 1Gig Corsair XMS 3200LL Pro Series (Dual Channel) 2-3-2-6-1t His Excalibur IceQII X800XT Audigy 2zs 2x200gig WD SATA Raid 0 Marvell Gigabit Onboard Logitech MX510 usb Antec True Power 550W WinXP Home sp2
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11-04-2003, 07:45 PM	#7
WarpSpeed Quod erat demonstratum Join Date: Apr 2002 Posts: 195	It's not simply a matter of total wattage or max amperage, but the stability of the PSU output is critical, especially if you are really pushing your components. A cheap 450 watt unit might perform much less well than a good quality 350 watt unit. __________________ IS-7, 2.6C @ 3.45GHz, 2GB OCZ PC3200, Antec 500, W2KSP4
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11-05-2003, 12:24 AM	#9
BBThumper Happy, Joyous and Free Join Date: Jun 2003 Location: Philly Posts: 2,024	........I have had alot of sucess with that 350w, saved me 3 times so far when a 400 and 2 450w PSU's just wouldn't boot a system ........... __________________ ASUS M3A32-MVP Deluxe AMD Phenom 9600 XP-90c w/ a T.T. 92mm fan 2 x 2gig pc26400 Nvidia 8400 2 x Raptors in Raid 0 ......My City's moto: Welcome to Philly, now get the heck out!!!!!!!
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11-05-2003, 01:21 AM	#11
8itgreat Registered User Join Date: Mar 2003 Location: Oregon (From Toronto) Posts: 793	i use an antec 350W Smart Power with no problems at all...i oc about 600mhz to 3ghz ....but my vid card is a geforce 4 Ti4200 128 mb....i know if i dropped a high end ATI in there i would be upgrading my psu for sure....not sure if i updated my specs here yet ....added an audigy 2, tv tuner card leadtek,,,,if its not there....and all is well with a bit of room to spare
(Offline)

11-05-2003, 02:03 AM	#12
BBThumper Happy, Joyous and Free Join Date: Jun 2003 Location: Philly Posts: 2,024	.......its because its a DFI ................... __________________ ASUS M3A32-MVP Deluxe AMD Phenom 9600 XP-90c w/ a T.T. 92mm fan 2 x 2gig pc26400 Nvidia 8400 2 x Raptors in Raid 0 ......My City's moto: Welcome to Philly, now get the heck out!!!!!!!
(Offline)

11-05-2003, 12:14 PM	#14
Sierra_abx Registered User Join Date: Sep 2003 Posts: 13,880	Many PSU makers will use peak power ratings when marketing their power supplies. Under normal circumstances, you will never see peak power. So a PSU rated at 450W may actually be giving you only 350-400W. And as the temperature inside the case heats up, the amount of available power will go down, which is why good ventilation is a must. Your friend's 250W PSU is probably not going to be enough. There is a lot of power-hungry equipment. Many P4 boards, for instance, require additional power through a ATX12V connector. It's worth the money, in my opinion, to buy a quality PSU because a bad or weak power supply can wreak havoc with your system.
(Offline)

11-05-2003, 02:01 PM	#15
skurge13 Registered User Join Date: Nov 2003 Posts: 19	Thanks for the awesome help, guys, and the advice on who the quality manufactureres are.
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