Anyone tried a Coolmax?

[Herb W.]

Those of us looking for a 400 watt+ power supply that is quiet don't have too many good options right now. I was wondering if anyone had tried the new Coolmax PSUs - they are getting great reivews the last few weeks showing rock-solid rail voltage at load, and although they have no fewer than THREE fans, they do have a three position switch allowing auto-regulation via temps as well as a manual low-speed setting. Reviewers have said that this PSU is extremely quiet at the low setting, although that could mean anything.... any experiences out there? These units appear well-made with huge heatsinks, but are a lot cheaper than the high-output Ultra-Quiet PSUs.

[powergyoza]

I looked at the reviews of 2 different versions (470 & 550) and I don't like it. 3 fans is overkill for a PSU. The heatsinks are a good size. The combined power output of the 3.3 & 5V rails on the 470 is less than what my Antec 400W can do. Dissapointing. The cables are also too long. I'd stick with the recommended PSU's on the Recommended page.

[Herb W.]

Thing is, I will be getting a P4, and they draw their ~ 9A (when OC'ed) from the +12 volt line - I have found that after doing the caluculations for my system as suggested by a link given somewhere here that this +12 V power is the critical figure to look at - there is always plenty on the 3.3 and 5 V lines, but even some bigger PSUs are only capable of putting out 12-15 A on the +12 . For the 20% headroom recommended over max draw, I need 20A (240 Watts) on 12 V for my config... If the Truepower 430 is drawing max A allowable on its 3.3 and 5v rails there are only 17 A left for the 12 volt. Probably an unrealistic scenario though, to have everything drawing full power simultaneously.

The reviews I have seen actually commended the Coolmax for having shorter cables than some of the other premium PSUs. And if their fans are really running quietly on their low power setting, 3 fans may not be much of an issue - that's why I would like to hear from someone who has heard the thing.

[MikeC]

While I have not tested seen or heard a Coolmax, everything about it looks like a clone of the Vantec 3-fan PSUs. These PSUs are not made by either Coolmax or Vantec -- they're coming from some big PSU factory in China. Bottom line: NO WAY it can be quiet. 3 fans of the same noise level will be ~4-5 dBA louder than 1. BUT more than that, there is the added turbulence of the 3 fans producing conflicting airflows inside the PSU -- that's worth abother 4-5 dBA IMO. If you want quiet, don't touch it!

My plain spoken 2 cents.

[Herb W.]

I think I'll probably go Seasonic - if I can find a Canadian source....

Just pulled the figures for the 470 Watt Coolmax from the graph on the unit: at 30C, the 3 fans are going at 1500 RPM; at 40C, 2000 RPM; 50 C, 2500. These revs seem pretty low, but there are of course three fans. Somewhere Mike you laid out a way of estimating the noise from figures like this but now I can't find the message... could you let me know the link or the formula - tx.

Postscript - I just looked at the Zalman fan speed X temp graph and see that the fans on the Coolmax are rated to run significantly faster at 50C - 2500 RPM vs. <1500 RPM. And no doubt considerably noisier. Of course the Zalman is only a 300 watt supply.

[powergyoza]

I think I'll probably go Seasonic - if I can find a Canadian source....

Just pulled the figures for the 470 Watt Coolmax from the graph on the unit: at 30C, the 3 fans are going at 1500 RPM; at 40C, 2000 RPM; 50 C, 2500. These revs seem pretty low, but there are of course three fans.

From my educated guess and experience with Panaflos (which spin @ 1900rpm, default voltage), I'd say 1500rpm would make for a loud PSU.