Hello everyone, and thanks for reading. Given the layout of my case (the Sonata II), a single-120mm-fan-style PSU is not an option (tricky, tricky, antec). I'm looking at the Silverstone Zeus 560W or the Tagan TG600-U25. (I know these are more than I need right now, but I eventually aim to run RAID 5 with a much better gfx card and OC my cpu to ~3.0 GHz)

The loudest fan in my case is the 107mm fan on my AC 64 Freezer Pro running at 2425 RPM (no pwm), and I'd like to keep it that way. I'm hoping someone here can tell me how quiet the Zeus really is (I've read reviews for the Zeus 650 and listened to it on 3dgameman, too loud), or maybe you have another suggestion for a 550W+ quiet PSU, that doesn't have a 120mm fan on the bottom.

Also, maybe someone can tell me, how noisy are the Fortron Source Group FSP600-80 and FSP700-80 models?

Thanks again for reading.

Hi, the Neo HE is a very quiet 80mm fan PSU. The early ones had compatibility problems but should all be sorted by now, Antec's RMA process is pretty good for those that got problem versions. The biggest version is 550w, but NO PSU is going to be quiet delivering that kind of power level. As you already have a 2400rpm fan your PC isn't that quiet so even if the PSU ramps up you won't notice.
May I ask what system you're running? I read about a Quad-core, 8800GTX SLI system that was run off a 500w PSU with no problems, peak load was ~430w (unknown if that's AC or DC figure)
You mention Freezer 64 so guess you have an AMD CPU, at stock speed the hottest, older models, are <100w. With heavy OC and over-volt I guess you could get to 150w (cooling be fun at that level!), most power hungry video card is 8800GTX ~135w, HDDs <10w, ~15-30w for motherboard, RAM, fans etc. I guess with 8800GTX SLI, big overclocking and lots (5+) HDDs you could break 500w. If your intensions are less extream a smaller version maybe equally suitable and cheaper.
Hope this helps, Seb

Why is a single 120mm fan PSU not an option?

The Seasonic S12-430 in my Sonatawas one of the four best quieting mods I made. The other three:
- replace noisy, failure prone NB fan with passive Zalman heatsink
- replace noisy GPU fan with passive Aerocool VM-101
- upgrade CPU HSF to Thermalright XP-120 with Papst fan at 6-11V

Hello,

Push/Pull fans are inherently noisier, especially if the fans are different sizes. It only helps in higher pressure situations, but in more ideal situations it just adds noise. Two fans in series do not move any more air than just one fan does.

agreed. It only helps move more air when there is an obstruction.

In a free air situation that would be true, but the inside of a PSU is generally very restrictive. In that case the higher pressure of the two fans in series can lead to higher airflow than just with one fan.

hey guys, sorry it took me so long to get back to my post. thanks for the info. I'm beginning to think that I don't need as many watts as I think, even after upgrades and hoping that the psu will last 3+ years.

dfrost (or someone else who knows),

how much should I worry about the 120mm fan on the belly of my future psu sucking hot air from the cpu into the psu? my rear tricool blows at about 1200rpm and 39cfm, and the 107mm fan on the a64 freezer pro blows directly towards the tricool at about 2400rpm and 40cfm. since the rear tricool will be spinning faster than the psu fan (my understanding is that they blow at ~950rpm) and therefore moving more air, will the majority of the heat be exhausted through the tricool? how about if I replace the a64 freezer pro with a ninja rev b, spinning at 1200rpm and moving 49.5cfm?

it seems to me that the air that the psu intakes has to come from somewhere, and the fins of the a64 are about 1.5in below (directly below) the 120mm fan on the psu, while the rear tricool is ~3.25in away from those fins. I know that any psu I buy will be rated for heat, and that it won't approach its rated max in my system regardless, but I also know that lots of additional heat is a bad thing for the lifespan if not the daily functioning of a psu.

Many, many thanks to anyone who can help me with this.

hi six4withafro

i'd like to share some experience since i'm running a similar system - a p150 case (same as solo) with s12 430 120mm bottom fan, a back mounted case 120mm scythe fan at 600-800 rpm and a ninja with 92mm fan at 600-1000 rpm

even when the system is under load (oblivion, a few hours sometimes) the psu won't ramp up. the air expelled by it is heated up to 40+ celcius degrees (EDITED here - made a typo, wrote 50 instead of 40), true, but still the psu remains quiet. i can't tell if majority of hot air escapes via the pus or the case fan, but i'm more inclined to say it's the case - that's what my calibrated hand tells me when i put it close to the back of the case

of course, for gaming i set the back case and ninja fans to max (which still is v queit) and there are no thermal problems. cpu stays at 50-52, nb is 35 max, gpu - usually below 60 even with the fan at low speed.

my point is - with a psu like s12 430/500 that won't be afflicted by higher temps, you don't have to worry about a thing.

things were a bit different when i tried the psu that came with the case - antec neohe 430. even when i ducted the psu, it would ramp up much quicker and work significantly louder that the s12. mind you - it didn;t have access to hot inside-case air, it was ducted directly to the front of the case and could draw fresh & cool air. still, it would work louder, so i stayed with s12 (i had it eralier, before i got the case)

one other thing you (and i) could do to decrease temps and noise is to try and duct the ninja to the back case fan. i'm personally too lazy for this tho...

hope this somewaht chaotic portion of info helps

Greetings,

It doesn't matter very much where the fan is located on the PSU -- if the PSU is located near the top of the case, then all air around it is warm, and the fan (no matter where it is located) has to move that air through it.

If there is any difference at all, the 120mm fan on the bottom will have slightly cooler air, since it is lower down -- and because it blows more air than a 80mm fan.

If the air flow is restricted, then two fans is going to be noisier than a single fan in a system with better air flow. So, the quieter solution is not to add more fans, but improve the air flow.

I measure PSU exhaust temperature with an infrared thermometer in all my thermal tests. (Yes, I know it isn't especially accurate, but I attempt to be consistent for decent relative measurements.) The PSU fan is less then an inch away from the Papst fan on my XP-120, and the Nexus case exhaust is not much farther.

With the S12-430, the exhaust temperature under 100% sustained load is typically only 7-10C above the idle temp. In the signature configuration, the highest load temp I've seen is 37C, but is more typically 30-33C (at 19-23C ambient room temp). The idle condition is much more typical with my PC usage, and that is usually only a few degrees above room temp. BTW, the exhaust temperature dropped several degrees when I switched to that Nexus exhaust fan running at 8-12V (thermally controlled by a MB fan header).

I never made this measurement with the original Sonata TP380S PSU, but It would have been substantially higher - the exhaust air from that PSU always felt warm, unlike the Seasonic's.

So to answer your question, I don't think you have to worry at all if you're using a high quality and efficiency PSU like the Seasonic, and a decent exhaust fan.