[lug] Question about new system

[D. Stimits]

Zan Lynx wrote:
> On Tue, 2005-03-08 at 17:32 -0700, D. Stimits wrote:
> 
>>Chris Brotherton wrote:
>>
>>>I am planning on building a new amd 64 machine.  Here are the specs:
>>>
>>>AMD 64 3200
>>>ASUS A8V Motherboard
>>>1 gig memory
>>>2 x 160 GB Hard drives
>>>1 CDROM
>>>Video Card without a Fan
>>>
>>>My question is how big of a power supply will I need?  Others have recommended
>>>a 400W power supply, but I am not sure if I need that much.  
>>>
>>>If I do, can anyone recommend good cases?  I usually use ANTEC, but the online
>>>vendor I usually go with only has cases with 350W and they don't have ANTEC
>>>cases without a power supply.
>>
>>When you don't have sufficient power supply, but it is close, you will 
>>have some memory errors that look like bad memory, or drives that have 
>>errors and it isn't really the drive's fault. If you add more drives, or 
>>a bigger/better video card at some future date, you will probably regret 
>>the smaller power supply. With AMD I also have not known them to be 
>>particularly tolerant of momentary power drains such as from a hard 
>>drive starting. You might get away with a smaller supply forever, but it 
>>probably isn't worth getting a smaller supply if you plan to keep the 
>>machine and maybe upgrade it over time (especially if you upgrade the 
>>video and add drives).
> 
> 
> The power supply rating in watts is one thing to look at, but the other
> is the brand name and if it has power factor correction.  With a power
> supply brand with a good reputation you don't need anything like a crazy
> 600 watt supply.

SuperMicro is one of the brands that deliver what they say they will, 
they're best known in server markets rather than home consumers though. 
The thing about many of their systems that offer 600 watt or up is that 
they were intended for dual or quad Xeon. Their low end cases are 
generally designed to support at minimum dual CPU.

> 
> In most power supply problems it isn't the lack of total wattage that
> kills, it's the lack of it on one of the power rails like the 12V or 5V,
> or it's too much fluctuation in power levels when components come on or
> off or someone turns on a vacuum cleaner.

 From what I've seen this is the reason as well...not averages, but 
peaks. I never want to touch a machine that doesn't have an UPS that 
deals with brownouts, but my comment on insufficient power was more 
related to internal surges, e.g., a hard drive startup, or changing 
video modes with a graphics card that runs high scan rates and frame 
rates. I wish more supplies had current ratings on their individual 
connectors, and that some sort of monitoring were available to show peak 
and average current loads.

> I run a dual 1.6 GHz AthlonMP system with a nVidia 5900 and 5 hard
> drives on a 475 watt Enermax supply without any problems.

I have an old P2 450 I'll trade ya for :P

D. Stimits, stimits AT comcast DOT net