Is a 350W PSU enough power?


M

Martin C

I will be considering doing a self build PC in the near future as my current
system is way too old.
I was thinking about buying the Antec SLK1650B case, which comes with an
Antec 350W PSU in the price of the case.
My new machine will not be state of the art, probably more like the
following:-

ASRock 939 Dual-SATA2 motherboard
AMD Athlon 64 3.2GHz CPU
3 hard drives,
2 optical drives (maybe just the one, but I want to consider the possibility
of having 2)
GForce 6800 graphics card (or equivalent)
1GByte RAM

And apart from the usual things like USB scanner, joysticks, graphics
tablet, mouse etc, that is about it.

Although at present, I do not play much in the way of stressful games (for
the computer that is), I will obviously be able to play more modern games
with the significantly upgraded machine.

I will probably want to overclock the CPU, but not by much. I prefer to have
a more stable machine with a bit more power than a potentially unstable one
with much more speed.

I have been told that any system these days with decent specs needs to
consider a PSU with 400W minimum.
Is this statement correct, or will the Antec PSU supplied be sufficient for
my needs since Antec is quite a good make.

Thanks for any help you can provide.
 
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C

Chris Hill

I will be considering doing a self build PC in the near future as my current
system is way too old.
I was thinking about buying the Antec SLK1650B case, which comes with an
Antec 350W PSU in the price of the case.
My new machine will not be state of the art, probably more like the
following:-

ASRock 939 Dual-SATA2 motherboard
AMD Athlon 64 3.2GHz CPU
3 hard drives,
2 optical drives (maybe just the one, but I want to consider the possibility
of having 2)
GForce 6800 graphics card (or equivalent)
1GByte RAM

And apart from the usual things like USB scanner, joysticks, graphics
tablet, mouse etc, that is about it.

Although at present, I do not play much in the way of stressful games (for
the computer that is), I will obviously be able to play more modern games
with the significantly upgraded machine.

I will probably want to overclock the CPU, but not by much. I prefer to have
a more stable machine with a bit more power than a potentially unstable one
with much more speed.

I have been told that any system these days with decent specs needs to
consider a PSU with 400W minimum.
Is this statement correct, or will the Antec PSU supplied be sufficient for
my needs since Antec is quite a good make.


I wouldn't do it; I'm running an Antec 450, and for a 3200 I probably
wouldn't go below 400. If money is tight buy a cheap case and a good
power supply, the supply is much more important than the box.
 
P

Paul

"Martin C" said:
I will be considering doing a self build PC in the near future as my current
system is way too old.
I was thinking about buying the Antec SLK1650B case, which comes with an
Antec 350W PSU in the price of the case.
My new machine will not be state of the art, probably more like the
following:-

ASRock 939 Dual-SATA2 motherboard
AMD Athlon 64 3.2GHz CPU
3 hard drives,
2 optical drives (maybe just the one, but I want to consider the possibility
of having 2)
GForce 6800 graphics card (or equivalent)
1GByte RAM

And apart from the usual things like USB scanner, joysticks, graphics
tablet, mouse etc, that is about it.

Although at present, I do not play much in the way of stressful games (for
the computer that is), I will obviously be able to play more modern games
with the significantly upgraded machine.

I will probably want to overclock the CPU, but not by much. I prefer to have
a more stable machine with a bit more power than a potentially unstable one
with much more speed.

I have been told that any system these days with decent specs needs to
consider a PSU with 400W minimum.
Is this statement correct, or will the Antec PSU supplied be sufficient for
my needs since Antec is quite a good make.

Thanks for any help you can provide.

http://www.antec.com/specs/SP350_spe.html

OUTPUT +3.3V +5V +12V1 +12V2 +5VSB -12V

Max. Load 22A* 21A* 10A* 15A* 2.0A 0.3A
Min. Load 0.5A 0.5A 1A 1A 0A 0A

* +5V, +12V1, 12V2 and +3.3V maximum output: 340 Watts max
* +5V and +3.3V combined output: 130Watts

12V2 powers the CPU. 12V1 powers the rest.

                      Desktop       Spinup
                       12V1          12V1      
3 disk drives          1.5A              6A-7.5A        
2 optical              <1.5A (keydisk)     1.5A(boot)
cooling fans           0.5A               0.5A
6800GS               5A               <5A (maybe 2A)
Total 12V1           8A (gaming) 11.5 (boot from CD, drives
spinup)

Some Nvidia video power numbers are available in these two articles:
http://www.xbitlabs.com/articles/video/display/gpu-consumption2006_6.html
http://www.xbitlabs.com/articles/video/display/ati-vs-nv-power.html

You should look up the disk drive spinup current from the manufacturer
website, to get a more exact value. I think with just one disk
drive, things look pretty good. The spinup interval lasts about
20 seconds, and it is hard to say exactly what the current consumption
profile will look like, with the various loads. I used to think
that 2A each was a good generic estimate for max spinup current, but
have seem some specs for products lately that are surpassing the
2 amp number.

I think I would feel more comfortable with a bit more 12V1, if you
are going with three disk drives. With one disk drive there
shouldn't be a problem.

You can look on www.amdcompare.com for power numbers for AMD
processors. To compute the current take (TDP_Pwr/12V)*(1/0.90).
The 0.90 is a 90% efficiency conversion factor for Vcore.
If your processor was 89W, that would be 8.24amps from 12V2.
The 15A on 12V2 on the SP350 would be plenty for that.

Paul
 
M

Martin C

Thanks for the detailed reply Paul. It has given me a lot to think about. It
looks like I might have to upgrade the PSU to a higher output after all.

Thanks again

Martin
 
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B

bgd

Just go with it. I am still on a 300 watt antec with not exactly a
conservative setup. Power shortages are obvious at boot, if there is any.
Once in Windows, it uses less and allocates better than boot. Acpi sharing
etc.
 

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