New power supply, or risk replacing PSU fan with a Nexus?

PSUs: The source of DC power for all components in the PC & often a big noise source.

Moderators: NeilBlanchard, Ralf Hutter, sthayashi, Lawrence Lee, Devonavar

Post Reply
Slayer of Noise
Posts: 22
Joined: Wed Jan 11, 2006 1:35 pm

New power supply, or risk replacing PSU fan with a Nexus?

Post by Slayer of Noise » Mon Feb 13, 2006 11:08 pm

Hey guys. I'm hopefully on the last leg of my computer quieting trip that began back in 2004. The target of my inquiry is the power supply. Basically, I've tried cooling it before by replacing the noisy stock fan with an 80mm Panaflo, and later an 80mm Nexus real silent case fan. The Panaflo was a Chinaflo, and was worse than the stock fan. The Nexus would have been acceptable if it didn't have a fairly annoying click. Both fans had their noise made worse by what appeared to be disagreeable PCM in the power supply.

Recently I purchased another 80mm Nexus, hoping the first one I got was a dud. I have my doubts that it was, and if I open the product and find out that it's unsatisfactory, the company I bought it from won't allow an RMA; if I don't open it I get a full refund. So, getting to my main question: should I return the fan? I'm definitely leaning towards yes, for the following reasons:

-As mentioned, if I open it and I don't like it, I'm out all the money I spent. I don't really suspect the last fan I bought was a dud, either, so I'm risking it if I open it.

-My power supply has “65%+” efficiency, and is rated at 500W. This means it can, in theory, generate a lot of excess heat. Having only one 80mm fan in there, even if I ramp it up to near 12V, seems like it could be dangerous. Does anyone here, preferably with a gaming/performance-oriented system, run a power supply like mine with a lone 80mm fan and not have problems?

If I wind up returning it I'm probably just going to buy a new power supply altogether (probably a Seasonic 500W). Going through all these fans is eating up money and isn't getting my anywhere.

Slayer of Noise
Posts: 22
Joined: Wed Jan 11, 2006 1:35 pm

Post by Slayer of Noise » Wed Feb 15, 2006 3:12 pm

Could someone please reply? RMAs have a pretty short lifespan, and I need to ship this off by Friday, if I indeed am returning it.

The main thing I need clarification on is whether a power supply with "65%+" efficiency and 500w can be adequately cooled with a lone 80mm Nexus Real Silent fan.

SebRad
Patron of SPCR
Posts: 1121
Joined: Sun Nov 09, 2003 7:18 am
Location: UK

Post by SebRad » Wed Feb 15, 2006 3:34 pm

Hi, could you give us an idea of what sort of system you’re asking the PSU to power and how much of the system’s heat is going out through the PSU? The PSU only produces as much power as your system demand, if you system requires 100w then the draw from the mains will be ~150w (100w/65%) with 50w as waste heat in the PSU.
If your system is low power (watts not performance) or even moderate power with good airflow management to take heat out through case fans not the PSU then I would say that the Nexus will be fine. My system (Athlon XP 3200, Radeon 9600pro ~100-120w) has a 80mm Panaflo swapped in the PSU, which is not overly efficient, and the fan runs pretty slowly (guess 5-6v) all the time. It is still connected to the PSUs fan controller so I guess (hope) that if the temps gets very high the fan controller can speed up the fan. I should point out that my PSU has a duct so it gets NO hot air from the case, only cool room temperature air. See here.
Does your PSU have a fan controller or is the fan constant speed and what voltage are you running it at? Can you try the Nexus or Panaflo at 5v or 7v off a HDD power plug to check if it’s the fan or the power supply in the PSU that’s causing the problem?
In summary using Panaflo / Nexus in PSU:
Low wattage rig with heat going out through case fans = no problem!
High wattage P4 Prescott with big graphics card(s) and heat going through PSU = no way!

Hope this helps, Seb

jaganath
Posts: 5085
Joined: Tue Sep 20, 2005 6:55 am
Location: UK

Post by jaganath » Wed Feb 15, 2006 4:19 pm

The main thing I need clarification on is whether a power supply with "65%+" efficiency and 500w can be adequately cooled with a lone 80mm Nexus Real Silent fan.
In my opinion, no. Let's say your system is drawing 200W; at 65% efficiency that leaves your PSU pumping out 70W of heat; a Nexus 80mm fan at 12V is not going to satisfactorily evacuate that much heat on its own, not even close. Get a Seasonic and sleep easy.

Steve_Y
Posts: 214
Joined: Tue Jun 21, 2005 2:17 pm

Post by Steve_Y » Wed Feb 15, 2006 4:19 pm

I've got a few 80mm Nexus fans and none of them click so I think you were just unlucky with the one you bought, I think you'd be very unlucky indeed to get another bad one.

In a fairly low power system (Athlon XP 2600+, Radeon 9800pro, 1 hard disk) a 80mm Nexus @ 7v provides plenty of cooling for the PSU (an old 350W Enermax). The air coming out of the PSU is barely warm even when the PC has been used heavily, I'd run it at 5v if I wasn't afraid of the fan failing to start, and it's quiet enough at 7v.

I should point out that my case is an Antec P180, so the PSU is seperated from the other hot components. Maybe a duct to the PSU intake would be a good idea if you're using a case with a more conventional layout.

Slayer of Noise
Posts: 22
Joined: Wed Jan 11, 2006 1:35 pm

Post by Slayer of Noise » Wed Feb 15, 2006 8:22 pm

Thanks for the replies everyone.

My system has (trying to include only the important stuff):
A generic (non-quiet/modded) ATX case
1 SATA hard drive
1 disc drive
1 sound card
1 fan controller with three 92mm fans
1 Radeon 9800SE video card
1 Pentium 4 3.2 gHz processor (socket 478), with a Northwood core
1 Asus P4P800-E Deluxe motherboard

The most stressful activity might be some gaming along the lines of Counterstrike Source or Battlefield 2. The power supply fan is assisted by a 92mm Nexus real silent case fan exhausting air in the back of the unit. It's running at 12V now, because the power supply drowns it out, but I'd probably run it around 7V once I get the power supply quiet. I do not have a duct and definitely don't desire to make one.

The fan was tested in the power supply and outside it. The power supply made the clicking worse, but it was still there at all voltages outside the power supply.

So, I'm not sure. It seems that, going by the responses of two of you, I might be able to get away with modding the unit. I am prepared to run the Nexus at a pretty high voltage. Even so, a failure could mean my whole system is lost, so...

I'll have to think this over!

Post Reply