What good is 400W supply vs. 300W one?

Sledgedog · Post by **Sledgedog** » Fri Aug 27, 2004 10:55 am

The whole question is not in the topic, but let me explain. I'm thinking about buying a 300W Zalman or a 400W Zalman, or a 300W Seasonic. I'm wondering if a 400W Zalman is quieter than a 300W Zalman if, for example, my system needs a continuous 100W but no more, and never more than 200W peak.

What are the actual differences in those two power supplies? Is the heatsink or fan somehow different? If the heatsink is bigger in the 400W version, then it would be more silent at 100W output than a 300W version. But the only difference could as well be that the fan runs faster in the 400W model at a certain temp. and thus the 400W model would have more peak output, but would even be noisier at 100W output than a 300W model.

This could be one way with Zalman, and the opposite way with Seasonic Super Tornado. Please tell me as much about this as you can.

Tigr · Post by **Tigr** » Fri Aug 27, 2004 1:21 pm

With the Zalman, the two power supplies are actually quite different from each other. They differ in some design and some parts.

For one thing ZM-400 is about twice as heavy as ZM-300. Ok, I am exaggerating, but it is close. The weight of the PSU is (more or less) directly proportional to the quality of build

At least, the heatsinks are much heftier.

ZM-300 also has those strange additional slots in the bottom of the PSU - the side of the motherboard. That will only make the PSU "grab" more hot air from the CPU heatsink, no good comes from that.

In my systems the ZM-300 is noticeably louder than ZM-400. Although I am nowhere close to consuming 400 or even 300 Watts, I fit ZM-400 everywhere simply because it is quieter. YMMV but I recommend buying the 400 Watt PSU if you go for Zalman. Cannot say anything about the others.

HammerSandwich · Post by **HammerSandwich** » Fri Aug 27, 2004 1:52 pm

The general rule holds that, within a given PSU family, higher-wattage models can handle higher heat. Some manufacturers let those PSUs run warmer before they speed up the fan, so a 400W PSU can be a little quieter than a 300W at, say, 150W.

You can see this at Seasonic's and Zalman's sites:
Seasonic S2FC graph
Zalman 400B
Zalman 300B

Sledgedog · Post by **Sledgedog** » Sun Aug 29, 2004 8:24 am

I saw pictures of the insides of both 300W and 400W Zalman models, and that convinced me, almost.

What I don't understand is, why is a 400W Zalman rated worse than a 300W one at silentpcreview.com? 300W model got 7 for noise, whereas 400W only got 6+, and I don't get any clarification to this from the comments. As far as I know, the reviewed 400W model is newer than the 300W model.

I'm only one click away from ordering a 400W unit, but I'll wait a bit if some unexpected information turns up.

Sledgedog · Post by **Sledgedog** » Sun Aug 29, 2004 11:11 am

I did it. Will get one 400W Zalman tomorrow. Flipped through reviews like crazy at the last minute, but decided that Zalman is the best available here. No new Enermaxes are yet here, and 400W Nexus wasn't convincing enough.

Please, do answer my previous question anyway if you have any thoughts about it.

I certainly hope this Zalman will be better than my soon dying 430W Antec TruePower. Soon dying because it got a loud coil whine some days ago. In the meantime I'm running a very old 234W Enermax that is barely adequate for the task. I'm afraid that if I were still using the Antec, it might take my MB or a HD with it when it finally goes.