How many USB devices is too many for a 350 watt PSU?

[squirtle24]

Hallo,

I visited home recently and fixed my Dad's malfunctioning computer, or so I thought. It would consistently freeze(oddly enough, every time I opened OE6), so I suspected the power supply. I changed it from the stock PSU to an Antec Blue 350 Watt. Perhaps I should have ordered a bigger one from Newegg, in retrospect. At any rate, the new PSU fixed the freezing problem, at least while I was testing.

Now my dad claims it's still randomly crashing when he's using it(screen goes black, and can't be restored without reboot). I installed the UD Agent from grid.org, and it runs 24/7 without freezing the machine. I'm pretty sure the CPU is fine and the computer is stable so long as my Dad(the destroyer of computers) isn't using it.

Anyway, he has a tendency to connect a bunch of USB devices at the same time, so I was wondering what the upper limit would be for a 350 watt power supply. Let's see, the computer has an Athlon T-bird, DVD burner, CD burner, internal Zip, old ATI All-in-Wonder 128, NIC, and he connects things like an external HD, external USB Zip, PDA, graphics tablet, and maybe some crap I don't even know about.

I figure it's either this or some bad hardware, but I find it odd that the computer can basically do number crunching all of the time, but will onlly crash when my Dad uses it. Thanks for any advice.

 

[RaiderJ]

I highly doubt that USB devices could draw that much power. Maybe if you have 128 or so.... I'd check other hardware.

 

[Sheriff]

More likely a SW problem with JAVA on Opera and unless you have 12+ USB devices running at once then I would look elsewhere (ie.HW/and even SW driver updates,)

 

[Boogak]

You could always get an external powered USB hub if you suspect it's the USB devices.

 

[Dug]

Don't worry about the power from the power supply.

What he should be looking at is where all those devices are being plugged in.
Obviously he is using a hub. Not all hubs work well in regulating power. (Assuming he has a powered hub.)

There is also a known problem with VIA usb controllers, in fact there is a Microsoft page on how they don't support specific models.

Try getting a usb pci card from Keyspan or IO gear, and run from that.

Just adding a powered external usb hub won't necessarily work because its still going through the VIA usb ports. (I'm assuming this is what he has.)

 

[Sheriff]

Originally posted by: Boogak
You could always get an external powered USB hub if you suspect it's the USB devices.

Not to crotique but hubs won't help (esp if there are enough ports already) and many devices won't work there.

 

[EeyoreX]

You could always get an external powered USB hub if you suspect it's the USB devices.

Not to crotique but hubs won't help (esp if there are enough ports already) and many devices won't work there.

Unless I am confused, it seems to me that if the problem is in fact to many USB devices drawing power from the PSU, that an externally powered USB hub would help, as the power would now be supplied by the hub and not the computer. At least that is how I always understood the rationale behind powered USB hubs...

\Dan

 

[Sheriff]

Dan, It may help but my Printer(s) and Scanners won't work on a hup, even with the extra power and many hubs do not have that feature so I didn't consider that!

 

[corkyg]

I have not seen a printer or scanner that did not have its own power source - only the data goes via USB for those critters. I have found that a USB link is unreliable for a laser printer that goes to sleep or is not often turned on. The old LPT1 works best there. My scanner is either USB 2 or Firewire - I use Firewire because in my experience, it is more reliable than USB. USB sometimes just loses it. But - a powered hub is an asset - especially a USB 2 rated hub.

 

[squirtle24]

Thanks for the input, guys. I'll probably just back up everything and reinstall W2k the next time I'm there, using updated drivers and whatnot. It's been about two years since installation, and he's installed all kinds of random stuff since then.

He does use a hub, but I don't believe it has its own power source. Still, I think he's been using the hub for a year or so, and the problem has only recently shown up. Bleh, I dunno. I'll ask him to stop using the hub and see if he still has the same symptoms. Thanks again.

 

[ViRGE]

Just for the record, USB is rated for 5V @500ma, or 2.5wts per root port. That works out to 20wts total max for most high-end boards, which have 8 ports.