Power supply stupid question

[edfreeman]

I've been experiencing some random re-boots and lockups (plus, as a key symptom, the fans seem to change speed a lot), and after reading some posts in various forums, decided to dust off that little program called motherboard problem. My suspicions were proven true when the program told me that both my 12V and 3.3V (that runs the memory, I think) had periodic voltage dips that set off the program alarms (the 12V went to 8.8 V and the 3.3 went to 2.7). So, I've concluded that I need to upgrade my 235 W power supply, as the one in the case is either inadequate or failing. My question is, are the dimensions and mounting pattern of all case power supplies the same? I measured the one I have, and it seems to be 6 inches wide, 3 1/4 inches tall, and 5 1/4 inches deep. No vendor or manufacturer seems to list these dimensions. I plan to get a 400W (yeah, I know, probably more than I need, but I run 3 hard drives, a burner, and an extra case fan . . . ). Thanks in advance

 

[natto fire]

i am fairly sure that they are all the same. May I reccomend the Enermax Whisper 451w?

 

[Shmorq]

Most likely, your power supply is in ATX form factor, so upgrade it to another ATX one. Also, I would look for the newest ATX 2.03 so that the new supply will be compatible with the newer motherboards from Intel. They have extra connectors which supply extra power to peripheral devices.

 

[Davejj]

You could also try a dual PSU setup, keep the more powerfull one for you mobo cpu, and the other for your fans etc.

Rig

 

[compudog]

Practically every power supply is the same in dimension. There are a few exceptions such as OEM, server cases etc. Many AT power supplies will physically fit in an ATX case and vice-versa. I just yanked a Dell ATX out of a Dell case and replaced it with a standard AT P/S to fire up an old mobo. Again, there are exceptions. If you go to a local computer shop, take the old one with you to compare. If you're ordering on line, I would guess 90% of what you would run accross will fit your case. As for going with the 400W, you can never have too much power!!

 

[SonOfZeuz]

Virtually all PCs made in the past three to four years use an ATX power supply, which has a dual-row motherboard power connector. Older PCs may have an AT power supply, which uses two single-row power connectors. AT power supplies also have a thick black cable that runs to the system switch. (ATX supplies are switched from the motherboard and don't have a switch wired to them.)

Note that although most ATX supplies are the same size, the physical size of power supplies does vary. AT supplies come in several shapes and sizes; what's called a "slim" supply is the most common.

Also, a few PC models use proprietary power supplies that can't be replaced with standard units. If your PC uses one, you'll have to order a replacement directly from the manufacturer.

It's crucial to purchase a power supply that matches or somewhat exceeds the power needs of your PC. Each component requires a certain amount of power. Using the chart below, add up the power requirements of your PC's components, and then add another 30 percent for "wiggle room." Most systems will do fine with a 250- or 300-watt supply; there's no advantage in purchasing a supply with considerably more capacity than your system needs.

COMPONENT WATTS
motherboard 15-30
celeron 700 21
pentium 3 33
athelon 70
ram 7/128mb
pci card 5
network card 4
graphics card 20-50
floppy drive 5
cdrom/dvd/burner 10-25
ide hard drive 5-15
scsi drive 10-25
10k or 15k scsi 10-45
case fans minimal

 

[ddeder]

Any idea how many watts a 700 MHz Duron uses?

 

[edfreeman]

Thanks to all for the excellent information. I do have an ATX system, so I confidently ordered my power supply. Using SonofZeus's numbers, I added up that I could be OK with the 300W standard, but, hey, I'll upgrade before the end of the year, and who knows what gadgets I'll want to run . . .