Power Supply Heatsinks - How Hot?

[larrymoencurly]

Is it normal for the heatsinks of an Antec SmartPower 300W (single fan, variable speed) to run 10-15F hotter than those of other 300W PSUs with a variable speed fan? I thought something was wrong, but a second identical Antec got just as hot.

I ran each PSU for 15 minutes with the cover on (heatsinks ran cooler that way) and measured the heatsinks 30 seconds after turn-off (time needed to remove cover and stick in the probe).

The other PSUs had both larger and smaller heatsinks, and they seemed to run their fans with about the same flow rate (deflected a piece of cardboard hung by 2 threads to the same angle). Some PSUs had lots of holes in their cases, others had almost none. But in every case the Antec ran the hottest.

 

[larva]

entirely normal

I have a 300W Antec supply, model PP-303X. This unit served me well with my P3 rig, but really knew it when I upgraded to a P4. It blew hair dryer hot air, indicating overload. Voltages where not as stable as before, confirming it was at its limits. This unit is only rated at 160W on the 3.3+5V, very low for a 300W supply. I found that any of the sparkle supplies I had handy blew cooler air, right down to the 250W model. I settled on the 350W model for my machine, and set the Antec aside for less demanding chores. While far from being the end-all be-all of power supply characterisitics, any of the sparkle units out-weighs my antec noticeably. A good portion of the mass is beefier heatsinks.

 

[larrymoencurly]

I don't think I'm overloading this 300W Antec because a no-name, non-UL 250W PSU and a junky but UL approved 300W work fine and run cooler with the same load.

I'm worried that Antec's supplier used a run of faulty parts or designed the PSU wrong so it oscillates unstablely. I've read that such oscillatons can make the temps go way up.

 

[larva]

While difficult to trace back to root cause, it sounds like your supply is having a tough time of it. My 300W smart power runs cool until you throw the load to it. I still use the supply in my C433 secondary PC and under that type of load it's fine.