Very Hot Topower PSU

[oliroe]

First of all here's my system: -

Lian 6070 Silent Case
Athlon XP 2600
ATI Radeon 9800 Pro
768MB RAM
3 Internal case fans
Zalman Flower CPU cooler with 80mm Fan
Seagate Barracuda 80gig
Samsung SATA 160gig Hard Drive
Topower 470W PSU

Basically i'm trying to get a quiet PC but having a few problems. The Topower PSU is incredibly hot (too hot to touch, is this normal???) which leads to an internal temperature of 55C and CPU temp of 65C at idle. I believe that this temp is almost all down to the PSU as it is right next to the CPU. I don't think i need 470W so tempted to get a silent 300W.

Basically my question is can my setup handle a 300W PSU and is it normal for it a PSU to be so hot???

Was thinking of a Nexus 300, Zalman 300 or Silentx

Thanks in advance

Oli

 

[Ice Czar]

http://takaman.jp/D/index.html?english


and compare it to the specs listed on the PSU
then you build in a safety margin of from 1\2 to 1\3rd
by deducting 1\2 to 1\3 the value of the PSU's rated amps and see if it still fits
it actually varies with the distribution ratios your likely to need more +12V than +3.3V or +5V
(CPUs now being powered by the +12V primarily)
possibly more if it a long term infrastructure investment and there is growth built in
of if the veracity of the manufacturer is in question (generics tend to lie like dogs)
most 250 or 300 watt PSUs will actually run most configs, but stability has become an increasing concern with the tighter tolerances onboard (FSB)

There is a decrease in total capacity with the rise in temperature , which reduces your amps, the rated amp values where taken at 25C
while your likely operating temperature will be 40C (especially if the PSU is in the top of the case exhausting the CPU HSF) and that is roughly a 30% decrease

That is offset by the additive nature of the calculator, employing all tha maximum draw figures for the assorted components, something that will never occur

However it gets even more complicated if you have alot of drives and fans, where "spinup" draw can be 4 to 5 times as much and they greatly contribute to transient response overshoot and undershoot in some supplies at startup if there isnt enough +12V
and have led to the dual +12V rails seen in modern PSU (ATX12V v2.0) since isolating that from the CPU and mobo can be important depending

The way you torture a power supply is to give it a fluctuating AC feed to deal with (from surge to brownout), at the same time you ask it to deal with a really dynamic internal load change (like spinning up alot of drives) while still keeping the rails stable enough for the onboard voltage regulation components of unknown quality

Failure anywhere along the chain from too big a spike at the source to too long or high an overshoot or undershoot to the mobo, with too much ripple or noise for the onboard regulator to deal with and RAM or other components can go bye bye, ideally the power supply will trip off and protect your components, the operable range it has is largely what the difference in one PSU to another is about. And when it comes to a comparision of a flyweight generic, the whole protection scheme of shutting down in time really comes into question. And of course how stable the rails can be maintained, how low the AC Ripple and noise.

so if you elect to get a supply in the near future you have to ask yourself
if its going to be a true infrastructure investment
in the past that was typically true, now it a little tougher with more power hungry devices
PCI Express, video cards ect.

They recently added 4 more pins to the main connector from 20 to 24, and an additional 4 pin +12V auxillary power connector, (ATX12V 2.0) and the spec keeps jumping the total amps on the +12V rail (ATX12V 2.0 & 2.2), actually there are now two +12V rails and Ive seen power supplies that have Quad rails