PSU recommendation needed

[chrestomanci]

This is a repost from this thread over in FSP support that hardly anyone saw and no one replied to.

Hello, I am looking for a PSU recommendation, but I need the PSU fan to run and extract air from the case as well as cooling itself.

I have a Silverstone SG01 case that I am planning to build up into a system in the new year. From the picture below (of the back of the case), you can see that the motherboard goes at the base of the case, with the power supply above it and directly over the CPU.



Thinking about how best to cool the system, I think that it would be best if I arranged for air to enter via the vents in the sides, the CPU fan to be reversed so as to push that air upwards into the PSU, and then the PSU fan to extract the air through the PSU and out of the case. For that to work the PSU fan would have to run continuously and not shut down when the PSU internals are cool enough. If the PSU has a thermostat switch that I can set to a low temperature then that would do the trick, alternatively I could use a PSU without a temperature sensitive cooling feature or one where it could be switched off.

I realise that I could open the PSU and mod it to connect the fan directly to a 12 volt rail, but I would prefer not to void the warranty on a brand new PSU.

I know that when the ATX specification was original defined, it was normal for the PSU to contain the only cooling fan on a case, and for that reason the PSU was often placed directly over the CPU so that it draw hot air directly from it and out of the case. I also know that in the 10 years since then the heat output of CPUs has drastically increased, and PSU builders have fitted temperature sensitive fans, that only go on when the PSU temp rises above a fairly high threshold.

As for the rest of the PSU spec, something in the 400-600W range would be good, as would high efficiency and modular connectors. Obviously there need to be vents on the bottom of the PSU, and preferably a big 120mm fan.

Any ideas? Thanks.

[dave87]

Seasonic M12/Antex NeoHE - both made by Seasonic, both modular, (the M12 at least) has a temp sensitive fan - so when the air gets hotter, it should ramp up

[FatalSaviour]

Unfortunately, although the NeoHE is efficient, and very open at the back of the PSU, the single 80mm exhaust fan produces an insignificant amount of airflow, and is probably not going to be what you're looking for.
What CPU/Graphics etc were you thinking about installing in the system, just so we can get an idea of the heatload we're talking about?
If it's not too demanding, you may be ok, relying on the existing exhaust fans provided on the SG01

[chrestomanci]

Seasonic M12/Antex NeoHE - both made by Seasonic, both modular, (the M12 at least) has a temp sensitive fan - so when the air gets hotter, it should ramp up

Normal temperature sensitive PSU fans are why I have a problem in the first place. Modern PSUs can stand an internal temperature of around 70C indefinitely, so PSU manufacturers set the thermostats on the temperature sensitive fans so they come on and ramp up gradually at that temperature, because that is so much hotter than ambient it does not take much airflow to carry the heat away.

The problem for me, is that I am using the fan for case cooling as well, so I would want it to come on at around 30C. Older and cheap PSUs have fans that run continuously, but they tend not to be efficient or have big fans, and I got a shock from a cheap PSU once, so I know to avoid them.

What CPU/Graphics etc were you thinking about installing in the system, just so we can get an idea of the heatload we're talking about?

If it's not too demanding, you may be ok, relying on the existing exhaust fans provided on the SG01

Initially I was going to go for a Core Duo system, probably based on an E6300 CPU, and integrated graphics, however when the price for nVidia 8800 graphics cards drops in a few months, I will probably buy one. I was also thinking of upgrading to quad core in 18 months or so, again when the price comes down.

As I say, I could just mod the PSU, and if the one I choose works fine for a while I will be less worried about voiding the warranty, but I have been through 2 PSUs on another system of mine, so I don't want to void the warranty on anything before it has had a chance to go wrong.

[dave87]

Normal temperature sensitive PSU fans are why I have a problem in the first place. Modern PSUs can stand an internal temperature of around 70C indefinitely, so PSU manufacturers set the thermostats on the temperature sensitive fans so they come on and ramp up gradually at that temperature, because that is so much hotter than ambient it does not take much airflow to carry the heat away.

The problem for me, is that I am using the fan for case cooling as well, so I would want it to come on at around 30C. Older and cheap PSUs have fans that run continuously, but they tend not to be efficient or have big fans, and I got a shock from a cheap PSU once, so I know to avoid them.

Ah, sorry, I didn't realise how hot they had to get to ramp up

[amjedm]

I've just had a look at the review of the Corsair 520 on silentpcreview and now understand what you mean about the psu fan taking quite a while to ramp up.

Like you, I was reluctant to hack a new psu so have bought second hand ones and modded them.

I took the fans out of a Sharkoon (rebranded Noisetaker) psu and am using the psu chamber fan in a P180 to cool the psu.

The other psu I modded was a Seasonic Tornado 400W. I managed to break the fan connector in the psu so ended up connecting the fan to a Fanmate. Have now connected to a fan controller and the lowest voltage is 7v.

Edit: Have you read the psu reviews on SPCR? The fan in an Ultra X 600 (recently reviewed) ramps up quicker than the Seasonic/Corsair psus.

[chrestomanci]

I was planning on fitting a Silverstone SST-NT06 cooler as they suggest on the product page for the case. Does anyone know if is possible to fit a fan bellow the radiator so as to blow air up through it and into the PSU? If so and if I can get a good seal, then the PSU fan would become a lot less important.

[amjedm]

On some of the Thermalright (or at least one of them) heatsinks you can have the fan blowing up instead of down. I would opt for that unless you're sure the heatsink you linked to can have the fan blowing up or mounted underneath.

[EtheAv8r]

With the Seasonic M12, the main 120mm fan is temperature controlled, however once the Seasonic M12 rear 80mm fan starts up - it stays on at full speed untill shutdown. For me (and many others I would think) this is an annoyance, and I decided this was a dealbreaker - so I am going with a Seasonic S12-650 Energy+ for my new build.

However the M12 feature that stopped me might be just right for you.

Why don't you Email Seasonic (Europe) - I found them very responsive and helfull to my enquiries, which put another tick in the 'which PSU' selection box for Seasonic.

[chrestomanci]

On some of the Thermalright (or at least one of them) heatsinks you can have the fan blowing up instead of down. I would opt for that unless you're sure the heatsink you linked to can have the fan blowing up or mounted underneath.

If you mean something like the Thermalright SI-128 that Clunk is trying to sell then unfortunately it would not fit. There is only 75mm of clearance between the CPU and the PSU on that case (exactly the mini um as per the ATX spec), so very few aftermarket coolers fit. Intel and AMD stock coolers fit, as do some Zalamans, but hardly anything else.

This image from the Silverstone NT06 Product page might explain things better.


Thanks anyway.

[chrestomanci]

With the Seasonic M12, the main 120mm fan is temperature controlled, however once the Seasonic M12 rear 80mm fan starts up - it stays on at full speed untill shutdown. For me (and many others I would think) this is an annoyance, and I decided this was a dealbreaker - so I am going with a Seasonic S12-650 Energy+ for my new build.

However the M12 feature that stopped me might be just right for you.

Why don't you Email Seasonic (Europe) - I found them very responsive and helfull to my enquiries, which put another tick in the 'which PSU' selection box for Seasonic.

Thanks for the tip. I have emailed Seasonic (Europe), and taken a look at the Seasonic range at Scan. They are a bit more than I was expecting to spend, but if they do the trick it will be money well spent.

[EtheAv8r]

Following from the post by chrestomanci... I see this case is very small.... Modular PSUs are often longer (the M12 is) and require additional clearance to connect/disconnect the power cables, so it may not fit!