90W PSU my only option?

[luv2chill]

Hi gurus... I have just purchased one of those GallantWeb boxes that is essentially a tiny 810e board (FlexATX?) with onboard everything running a Celeron 633. It has one 20GB 7200RPM drive in it. The system is essentially a FIC Sahara 3810. I plan to wipe it off and use it as a NAS box.

The problem is that this thing has a Delta 90W PSU in it. It appears to be an extra small SFX style (about 4.9" x 3.9" x 2.1"). Normal SFX is 2.5" deep but this case won't accomodate anything more than 2.1". I have scoured the net looking for larger wattage power supplies with the same physical dimensions but haven't had any luck so far. From what I can tell, a 90W is all that will fit in this case.

So, given that limitation, is it out of the question to think that I could hook up two 7200RPM HDDs in this system? I know the original Sahara 3810 system had not only the HDD but also a slimline CD-ROM and floppy drive installed. Given that the GallantWeb doesn't have these, do I stand a good chance of squeaking by with only 90W?

In case it helps, the output of the PSU is as follows:

+5V 12A
+12V 2A

+5VS 1A
-12V 0.2A

Would it help to disable the onboard sound and usb? There is no AGP slot, and I will not be using any PCI cards since video and ethernet are built-in. As already stated the chip is a Celeron 633MHz with a passive heatsink.

Believe me if there's a way I can get a higher wattage PSU I'd do it in a heartbeat. But barring that, if 90W isn't enough power to feasibly power two 7200RPM HDDs + the mobo then I'm going to scrap this project.

Much appreciate any advice or insight!

l2c

P.S. I am cross-posting this from the cases and cooling forum because I'm not sure which place it belongs. More traffic here though for sure.

 

[SOSTrooper]

I don't think that's a problem. If you only have 2 HDDs & mobo/cpu/ram then it really should be efficent with a 90W PS.

 

[Lord Evermore]

Actually if he's only getting 2 amps on the +12V line, it may not be enough. AMD's little design chart (which someone linked in another thread) shows hard drives taking 2A per drive, while a CD drive would only be at most 1A. The motherboard itself might take 0.30A though disabling some of the onboard devices could reduce that slightly, although most of the onboard devices probably run on 5V or 3.3V, so the +12V line won't change.

A Seagate Barracuda ATA IV actually uses 2.8A on the +12V rail! I can't find specs for Maxtor drives. Western Digital lists their "performance" line as using 1.3A on the +12V line, while their "mainstream" line uses 1.7A. These are of course the maximum power usage during spinup. They use maybe 1A during read/write operations at the most (WD actually says only 350mA). It's the spinup that really takes the power.

Socket370 boards use the +5V line to power the CPU (Athlon and P4 boards use the +12V rail). The Celeron 633 should probably only take 3 or 4A, so the +5V should be enough since there will be very little else using that line. A Barracuda takes 1.2A per drive on +5V.

A couple of 5400 RPM drives may be enough reduction in power requirements to let you use that supply.

Here is another small chart to give you an idea of needs.

 

[luv2chill]

BUMP

Any other opinions?

l2c