Since when did we need 400 w power supplies?!

[erikiksaz]

I remember back then (which was like a year ago), 300 w power supplies were fine. now i'm reading that 300w power supplies aren't enough?! what is this, are thunderbirds taking up THAT MUCH wattage? or is everyone just running 4 hard drives with 3 cdrom drives these days? please enlighten me, because i don't want to buy a new powersupply. i thought my antec 300w powersupply was a good one too. would i still be able to run something like a 1.4 tbird at 1.x speed with this power supply? i'm just running one hard drive, 2 cdroms, geforce, nic, and soundcard.

 

[Ryan]

Ya, you'll be able to run it. Many people around here have MANY other things on their systems that require them to use a 400w psu.

 

[eeut]

maybe for overclocking benefits.

 

[TunaBoo]

Actually,

the main (only?) thing in your computer that draws off of the 3.3V rail of your PSU is your processor. So people needa bigger PSU so they have have more amps to their 3.3 V rail. A 300 watt PSU provides enough power on the 12V and 5V rails to run like 20 hard drives off of.

Better made PSU's often alloct more power to the 3.3V rail, so you can get away with a lower wattage one.

 

[McCarthy]

Since about 2 weeks ago (that I noticed).

 

[JohnnyKnoxville]

Yikes I was at fry's today and they had a 550 watt power supply.Guess thats the next step

 

[MrWhiteUK]

The AMD recommended power supply list for the 1.4 Tbird has supplies from 300W and up.

 

[LXi]

I think 300W is on the borderline now, back then it was OK because we only had up to 1GHz, maybe 1.1. But when 1.33 and 1.4 rolling out, we're definitely going to need more power. And it's not uncommon to load your PC up with bunch of devices and cooling fans. Trust me, your system stability can really benenfit from the extra power. Power supplies are often underrated. I recommend 350W or more for a fully loaded high speed machine.

 

[julianf]

since my 350w psu burned out thursday cause of me adding another disk...

 

[TonyB]

I got a K6-2 300 and 8 IDE hard drives, half running on the motherboards IDE channels and the other half utilizing a Promise ATA100 controller. All of this under Linux running on a 230W generic ATX power supply. The box acting as an MP3 Samba server and FTP server has been up and running for 5 months, 3 days, 13 hours and 24 minutes. So you ask whether or not you need a 400W power supply? Nope its all a bunch of marketing hype that they want you to believe so you'll go out and shell out $100-200 on an item that you wont ever need.

Edit: another thing i have to add, Am i ignorant to believe that since chips are advancing ever so fast with new chip manufacturing processes that run with the model, faster, cheaper, smaller, and less power that it also equals to we need to get bigger power supplies? Shouldnt it be that we should be getting smaller Power supplies? Correct me if i'm wrong but doesnt a P4 1.8Ghz run with less power and heat than say a P2-400??

 

[Bozz]

I have two 250W power supplies because the first one powers the computer, the second one keeps the two 70 watt peltiers running happily

 

[Bozz]

Might as well add my pointless post for the day, hey Tony, Willamette P4's suck

 

[Insane3D]

"I got a K6-2 300 "

Ummm...where not talking about a 400W PSU for that "CPU", were talking about 1.4ghz and up Athlon systems. A K6-2 300 is not even in the neighborhood of the CPU's were talking about. The point is it's not the peripherals that are necessitating higher wattage PSU's, it's the high speed CPU's current draw on the 3.3v rail...

 

[TonyB]

I was confused on this subject so i went ahead and did a little research. I found on Anands site for their 1.33/1.30 Athlon article and found that the 1.33 draws a max of 42A and the 1.30 41A on the 3.3V rail of the PSU. Went to enermax's site to see their specs on their PSU's and this is what I found. The enermax EG265P-VP aka 250W PSU has a maximum output rating of 22A on the 3.3V rail; obviously not enough to supply an Athlon 1.33 or 1.3. Their EG365P-VE aka 350W PSU can do a max 32A at 3.3V, not sure if this is enough to do an Athlon 1.33 or 1.3 but they say its AMD approved. Their 550W EG651P-VD can do 40A max. Just for kicks i went to aMD's site to find out how much current my K6-300 draws and it comes out to 8.35A so i guess we really do need big powerful PSUs thesedays.

 

[Bozz]

Welcome to switchmode power supplies!

You 250w power supply only draws 2 amps (at 110 volts) under full load and it can supply 20-odd amps at 3.3 volts!

Same as the switchmode power supply (voltage regulator) on the motherboard, it steps down the 3.3 volts and regulates it at say 1.8 volts so almost double the current is available (not quite because some is lost to heat as no switchmode supply is 100% efficient)

Cheers

 

[Bozz]

Further basic electronics FAQ-

Power = Volts x Amps

Amps = Power / Volts

Current multiplication = Input voltage / output voltage (this is an approximate assuming 100% supply efficiency)

lets say 1.7v core and 50 watt power drain

50w / 1.7v = 29 amps

3.3v / 1.7v = around 2

20a power supply x 2 = 40 amps capable of being delivered by motherboard

Cheers

 

[Jeff H]

I recently helped a friend set up an IWill KK266 (non-raid), TBird 1.2G C, 256MB PC133 Crucial PC133, IBM 60GXP 60G, Toshiba 16x/48x DVD, CD-RW, IDE Zip, Floppy, two NIC's, Sound, GForce 2 32MB, PCI FireWire. He bought the Enlight 7237 w/ 300w p.s., as I'd read of numerous successes w/ that case/p.s.

All was fine until he added the FireWire, and then nothing. Not video BIOS post, no BIOS screen, nothing. He pulled some cards, and up it came. Replaced the Enlight p.s. w/ an Enermax 430w and back in business.

 

[HannibalX]

Tbird 850 Mhz, GeForce DDR, 256 Meg Ram, 7200 RPM HD all on a 200 Watt power supply - don't buy in to the hype.

 

[TunaBoo]

<< Further basic electronics FAQ-

Power = Volts x Amps

Amps = Power / Volts

Current multiplication = Input voltage / output voltage (this is an approximate assuming 100% supply efficiency)

lets say 1.7v core and 50 watt power drain

50w / 1.7v = 29 amps

3.3v / 1.7v = around 2

20a power supply x 2 = 40 amps capable of being delivered by motherboard

Cheers >>



Good work, math looks right on!

Hard drives take between like .5 and .7 amps (normally). That is why they are no biggie. Your CPU is gonna draw 40 amps at 1.8 volts or something. That's a lot of juice.

 

[Jason Clark]

Trinitron, it is certainly not hype. You may have gotten lucky with your powersupply. But 200 Watt powersupplies do not put out nearly enough amperage. I'd love to see you fire up a 1.3 off that with a couple of drives and a cdrom.

 

[GrumpyMan]

Yeah Trinitron you are either kidding or somewhat lucky, either way good luck on adding anything else to your box.

 

[Adul]

trinitron must have a good 200 watt power supply.