Quality 300Watt psus are good enough for most

[indianduddawg47]

I researched all the amperage requirements of my components, added them together and calculated the total wattage. My computer needs 217 watts! And my computer is no slouch either... AMD Athlon 64 3700+, nforce 4, geforce 6600, raptor 10k rpm hard drive, 4 fans, 2 dvd burners....

Click here to see the chart

Anyway, even if you factor in 25% for overclocking, a quality 300 watt power supply will still supply nearly 30 spare watts.

 

[MobiusPizza]

Well good PSUs have typically 60-70% efficiency on light load and 70-80% on heavy loads.
217Watts / 70% = 310W

Also your values are theoretical / typical values. During heavy load no doubt the usage would be higher.

Luckily ur using 6600GT. The recommend PSU for X800XL is 400W, SLI is 500-600W depending on graphic card
which agrees with my calculation.

 

[KoolDrew]

A 300w PSu is really pushing it though.

 

[indianduddawg47]

Most of the values are peak values - for example, the Athlon 90nm has a peak usage of 67W... 67W/12V = 5.8A. That's 5.8A at peak usage... normal use will be substantially lower. All the other values are directly printed on the drives.

power supply efficency deals with AC voltage being converted into DC voltage. For example, a power supply with 80% efficency will take 375W of AC voltage and convert into 300W DC voltage, 75W heat.

 

[indianduddawg47]

Anyway, for most systems in the mid to high range, a 300 watt should hold it's own...

 

[MobiusPizza]

Originally posted by: indianduddawg47
power supply efficency deals with AC voltage being converted into DC voltage. For example, a power supply with 80% efficency will take 375W of AC voltage and convert into 300W DC voltage, 75W heat.

Yeah that's right.
A 300W PSU will output only 240W of DC power to the devices, at 80% efficiency. 60W of heat still goes to your electricity bill and tolls at the current drawn from the socket.

So to power your 217Watts PC you'd need 310W PSU.
If you don't believe me get a power meter through your socket.

In that case a 350W PSU without Overclocking is a safe bet, and I agree with that value.
For overclockers like me on a similar setup I am getting a 400W PSU.

 

[imported_whatever]

Originally posted by: AnnihilatorX
Well good PSUs have typically 60-70% efficiency on light load and 70-80% on heavy loads.
217Watts / 70% = 310W

Also your values are theoretical / typical values. During heavy load no doubt the usage would be higher.

Luckily ur using 6600GT. The recommend PSU for X800XL is 400W, SLI is 500-600W depending on graphic card
which agrees with my calculation.

The rated wattage is output, not input. So, a 300W PSU can (supposedly) supply 300W.

 

[MobiusPizza]

Originally posted by: whatever

Originally posted by: AnnihilatorX
Well good PSUs have typically 60-70% efficiency on light load and 70-80% on heavy loads.
217Watts / 70% = 310W

Also your values are theoretical / typical values. During heavy load no doubt the usage would be higher.

Luckily ur using 6600GT. The recommend PSU for X800XL is 400W, SLI is 500-600W depending on graphic card
which agrees with my calculation.

The rated wattage is output, not input. So, a 300W PSU can (supposedly) supply 300W.

Really? hmm
Well if it says so then it would
Sorry I was wrong
Confused with input and output.

 

[mechBgon]

Originally posted by: indianduddawg47
Anyway, for most systems in the mid to high range, a 300 watt should hold it's own in theory...

No offense, but... fixed. You want to try that, go right ahead. It may run fine (for a while, anyway), but my experience has been that reality trumps theory frequently in this area.

What's the cost of "supersizing" your PSU, maybe $20-$30? I bet we've all spent more than that on silly stuff like LED fans, etc. Look at the projected power-draw requirements for the next-gen video cards for another motive to overengineer your system in the PSU department.

G70 to be power-hungry

WE HEARD THAT Nvidia asked PCI-Sig, the PCI and PCIe standardisation body, to provide some more juice for Nvidia's next generation cards. It turns out that 75W from external connector and 75W from motherboard is not enough. Nvidia wants an additional 75W for its G70 card.

Eh? Possible 225W power delivery just to the video card. I'm not sure even my TruePower2.0 480 will hold up to that kind of onslaught, although I hope the actual power draw is closer to 150W than to 225W.

 

[Arcanedeath]

Also keep in mind most PSU's are rated at 25C and we all know it gets hotter in the PSU's than that so a 300 watt PSU at 25C is more like a 200 to 250 watt PSU at normal operating temps. thats the other reason to get higher wattage quality PSU's.

 

[mechBgon]

Originally posted by: Arcanedeath
Also keep in mind most PSU's are rated at 25C and we all know it gets hotter in the PSU's than that so a 300 watt PSU at 25C is more like a 200 to 250 watt PSU at normal operating temps. thats the other reason to get higher wattage quality PSU's.

^ another great point :thumbsup:

 

[indianduddawg47]

I'm talking about modern computers, not the next generation video cards. And also, by quality 300 watt power supply, I mean a quality brand that doesn't publish it's ratings at 4C.

To me, nowadays, everyone seems to emphasize wattage and disregard quality. It's more important to get a good quality power supply than a high wattage power supply. For example, this http://store.yahoo.com/maxcooler/noname54.html would hold it's own on most typical mid to high end modern systems.

 

[svi]

In theory, you are correct, a 300W PSU would power pretty much anything sane without any trouble. In practice, most PSUs are moderately to horribly overrated (meaning that they're spec'd for much more than they can put out in the real world, not that people think too much of them), so most of us end up with more. That includes what a lot of people think of as quality PSUs, as well; Antec and Enermax power supplies are overrated too, though not as much as Powmax units.

A PSU actually tested under real-world conditions to put 300W of DC power out for a long time would easily do the job, but unfortunately any such PSU would probably be rated higher to sell for more. There are exceptions, of course; I've heard that the Zippy/emacs 300W PSU for sale on NewEgg is a genuine 300W unit (tested at typical temperatures and everything!), so it should have no trouble powering most rigs. Of course, most people would rather spend $50 on a "400W" unit than $75 on a 300W one. Feh.

 

[shoRunner]

yes a quality 300 or 350 would power basically every computer except one with SLI

 

[mechBgon]

Originally posted by: indianduddawg47
I'm talking about modern computers, not the next generation video cards. And also, by quality 300 watt power supply, I mean a quality brand that doesn't publish it's ratings at 4C.

To me, nowadays, everyone seems to emphasize wattage and disregard quality. It's more important to get a good quality power supply than a high wattage power supply. For example, this http://store.yahoo.com/maxcooler/noname54.html would hold it's own on most typical mid to high end modern systems.

I agree that quality should be a primary consideration when buying a power supply. If you read the posts here in General Hardware, you'll find that the seasoned members are pretty much all onboard with that idea.

Running stuff at redline because some calculations showed it could be done, however, that ain't my style Would you buy a car built like that?

Salesman: this is the new Honda JustEnuf. It is light and aerodynamic, so it can cruise at 60mph on a mere 15hp. The engine does a full 20hp* at 6400rpm**, so that's more than adequate.

*at 2000ft altitude, 25C temperature, using premium fuel

**engine redlines at 6500rpm, see hp/torque chart for more details

 

[gf4200isdabest]

This topic has been posted half a billion times over the years - same conclusion every time: the PSU market is full of gimmicks. If your 300W PSU is operating properly, it would be a challenge to design a computer that could at any point use more than the PSU can supply...

 

[imported_michaelpatrick33]

MMMM PC Power and Cooling 510 watts at 50C. MMMMM

LOL. Now that is what I call dualcpu,dualgpu ready. Yeah baby, yeahhhhh! :laugh:

Or maybe even Dear God my power bill 85% efficiency :shocked:

 

[svi]

Originally posted by: michaelpatrick33
MMMM PC Power and Cooling 510 watts at 50C. MMMMM

LOL. Now that is what I call dualcpu,dualgpu ready. Yeah baby, yeahhhhh! :laugh:

Or maybe even Dear God my power bill 85% efficiency :shocked:

Ah, the obligatory PCP&C mention. It's nice of them to post accurate specifications, but their PSUs are overpriced (not badly overpriced, just overpriced). Shame.