how big of a power supply

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kolhydro

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the system in my sig runs perfectly fine right now, however, ive always thought that a 300 watt power supply was not really enough for it. [it is a 300watt antec though] i believe it could use it a bit more power, but i dont want to go overkill. any idea how big of a supply i should go for? thanks

-hydro
 
Must have 500W ++ :rolleyes:

If it's running fine, why do you need more power? Antec is a good brand. Your gut is telling you you don't have enough power?? If you're having problems, upgrade. If not... wtf?
 
ALOT larger systems than that run fine off 300w. Its all about quality power and having enough voltage on each line. The amps on each line allowed are much more important to look at then the wattage rating. Thats where they trick you. I guarantee you the largest of uniprocessor systems with 4-6 hard drives and 4 optical drives can run off 350w. I use an Antec 430w myself in my main rig. Its best to have a little bit larger supply when your buying them so they are more future-proof, and if they aren't worked as hard then they put out less heat and have less of a failure rate.
 
I always 400W+ is definately not needed...So many nasty Shuttles(P4 3.2, 9800XP, etc.) are running on Shuttle PSUs which are like 200W-300W...
 
Name-brand PSUs generally are more reliable than generic PSUs. I've seen a guy try a 500watt bargain-basement PSU and have his computer randomly reboot and fail to power up, upon which he replaced it with a trusty name-brand Antec which had a lower wattage (380, I think?) and had all his stuff work fine afterwards.

These name-brand PSUs often have voltage lines that are nearer to specification than generic models. When your voltage lines drop significantly on CPU load, you should know your PSU is creaking under the load... =\

If you check your voltage lines at CPU idle and check them again at CPU load, see if they are significantly different. If they remain at the same level, and if you aren't having any problems with your computer that could be power related (i.e., failure to boot, random reboots), hold off on upgrading that power supply until you upgrade your components or add new ones.
 
thanks for all the great advice guys. well i was planning on making a few upgrades, adding a new motherboard...either dfi's lan party 2 ultra or the newer gigabyte board with dual lan, gigabit ethernet, serial ata, ata raid 133...one of the expensive ones its like $120 now actually now that i just looked. [supports 400mhz fsb] then i planned on upgrading my cpu eventually as well im thinking a 2500+ or a 2800+ barton, might even go for a 3000+ barton. then ill be upgrading my memory to at least DDR 400 and at least 1024mb of it. im going to remove my cd drive and add another dvdrw [an 8x dual format] and also upgrade the video card to either a 5900 or a 9700 pro [if i can find one] or a 9800.

i was thinking that i might need to buy a better power supply for those upgrades coming soon. this 300 watt antec is around two years old now but its still kickin and still doin great and ive never had random reboots or anything of that sort. i just want to more or less add more power for further expansion over that. i was thinking a 430W or 480W. well anyways, i was just rambling, thanks for all the info and advice.

-hydro
 
Power Supplies: How big a PSU do I need?
AGP video card - 20-30W
PCI video card - 20W
AMD Athlon 900MHz-1.1GHz - 50W
AMD Athlon 1.2MHz-1.4GHz - 55-65W
Intel Pentium III 800MHz-1.26GHz - 30W
Intel Pentium 4 1.4GHz-1.7GHz - 65W
Intel Pentium 4 1.8GHz-2.0GHz - 75W
Intel Celeron 700MHz-900MHz - 25W
Intel Celeron 1.0GHz-1.1GHz - 35W
ATX Motherboard - 30W-40W
128MB RAM - 10W
256MB RAM - 20W
12X or higher IDE CD-RW Drive - 25W
32X or higher IDE CD-ROM Drive - 20W
10x or higher IDE DVD-ROM Drive - 20W
SCSI CD-RW Drive - 17W
SCSI CD-ROM Drive - 12W
5400RPM IDE Hard Drive - 10W
7200RPM IDE Hard Drive - 13W
7200RPM SCSI Hard Drive - 24W
10000RPM SCSI Hard Drive - 30W
Floppy Drive - 5W
Network Card - 4W
Modem - 5W
Sound Card - 5W
SCSI Controller Card - 20W
Firewire/USB Controller Card - 10W
Case Fan - 3W
CPU Fan - 3W

The wattage numbers above are estimates and may be rounded to the nearest 5 watts. The given wattage may only reach the specified level during power-up or during peak usage. Always purchase a power supply with a bit more wattage than you calculate you'll need, to make room for future upgrades.
 
Wow, you mean, I was running 650 watts worth of stuff on a 250 watt power supply? :eek: That's nuts, are you sure those figures are correct? I used to run 7 SCSI hard drives, 3 CD ROM drives, 4 IDE hard drives, a power hungry video card, and a Barton 2500+ at 2.3ghz on a 250w PSU (there was other stuff, too, that's just some of it)... Never a problem either, even monitored the rails using MBM5. o_O Since then, I've switched my SCSI drives over to their own PSUs...
 
Have you tried the power needs estimator at http://takaman.jp ? It seems to give realistic estimates and says that you need about 260W (150W combined +3.3V & +5.0V power), and a 300W Antec should have no problems with that because mine managed to run a 380W load without drooping too much (but my 300W Fortron/Sparkle and Delta drooped less).
 
if your rails are good, you shouldn't need to upgrade. But that number of hdd's is a bit high for a 300w, I would get a 400watt one. And as always with PSU's, you get what you pay for.
 
Most people run on a larger than needed PSU...But I guess it is to be extra safe...
 
This is one of the more accurate tables i have seen:

http://www.pcpowerandcooling.com/maxpc/index_cases.htm

Most all systems will never pull over 350w, even the larger server small server style cases. Unless you have dual processors or over 6 hard drives i wouldn't bother with buying anything larger then 400w as long as its a quality power supply.

Hard drives can be a bit tricky because when the spin up when you first start the pc they can draw up to 2.5x their normal wattage. It would be near impossible to max out everything on the system at once so i would just use the minimum ratings for each device and then add an extra 100w to that for headroom.

The main thing you want to look at on the PSU is its efficiency rating and its amps for each line and its combined allowed amps on the 3.3v and 5v lines. You want a PSU with lots of wattage allocated to the 12v line because thats the line that will get stressed the most.
 
Originally posted by kolhydro
the system in my sig runs perfectly fine right now, however, ive always thought that a 300 watt power supply was not really enough for it. [it is a 300watt antec though] i believe it could use it a bit more power, but i dont want to go overkill. any idea how big of a supply i should go for? thanks

-hydro
Click to expand...

You're fine. Right now I have a:

Barton 2500+
Asus A7N8X Deluxe Mobo
2x256 PC2700 RAM
Radeon 9800 Pro
2x40GB, 1x60GB, 1x120GB Hard Drives
CD-RW
DVD-ROM
Floppy

All running on a 350W Antec. When it comes to power supplies quality above quantity. There are plenty of 450W power supplies made by cheap manufacturers that we've never heard of, but I'd take my Antec any day.
 
Check my sig I run that on an antec 330W with no problems at all...
 
Originally posted by burningrave101
This is one of the more accurate tables i have seen:

http://www.pcpowerandcooling.com/maxpc/index_cases.htm

Most all systems will never pull over 350w, even the larger server small server style cases. Unless you have dual processors or over 6 hard drives i wouldn't bother with buying anything larger then 400w as long as its a quality power supply.

Hard drives can be a bit tricky because when the spin up when you first start the pc they can draw up to 2.5x their normal wattage. It would be near impossible to max out everything on the system at once so i would just use the minimum ratings for each device and then add an extra 100w to that for headroom.

The main thing you want to look at on the PSU is its efficiency rating and its amps for each line and its combined allowed amps on the 3.3v and 5v lines. You want a PSU with lots of wattage allocated to the 12v line because thats the line that will get stressed the most.
Click to expand...

6 hard drives... I had 10 (7 SCSI and 3 IDE) in one box for a while, along with a GSFX 5200, a CD Burner, a Barton 2500+ @ 2.3ghz, 4 delta style cooling fans, a SCSI card, a 5.1 sound card, and some other goodies. According to the calculator, that would come out to 400w draw, and I feel that is conservative (still had more goodies plugged in that wern't listed, it was eventually 7 SCSI drives, 3 IDE drives, 1 SATA drive, a CD Burner, a DVD ROM, and several game accessories, that should bring it up to about 450w draw. One IDE drive was using SATA via an adapter).
 
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