low draw, disable PSU fan Corsair

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

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dan
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low draw, disable PSU fan Corsair

Post by dan » Wed Apr 20, 2011 7:01 am

As I've stated previously, my Corsair has a rather loud fan, the VX450. While it is still under warranty, I don't think it worth it to ship it off.

I've thought about disabling the fan via a chopstick, so I don't have to open it up.

My case is well ventilated, using speedfan to spin down the fans, and I don't think the power draw is high. Uses passively cooled nvidia gts7600 and c2duo 1.86ghz, not over clocked, 1.18volts.

I don't know what my system draw is, but if it is under 200 watts, and I am using c2duo 1.86 undervolted and a passively cooled gts 7600 card, and well ventilated, can't I just disable the PSU fan?


Is there a certain amount of power draw that a computer takes that is so low that the PSU fan can be disabled safely, i.e 200 watts?
100 wats? 75 watts?

Laptop powerbricks do not have fans, granted that laptop don't require that much energy.

Tealc99
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Re: low draw, disable PSU fan Corsair

Post by Tealc99 » Wed Apr 20, 2011 8:11 am

Be careful going passive on a power supply that is intended to be actively cooled. Even a relatively small amount of airflow can cool components well enough but no airflow at all could be a big problem.

I would say swap the fan for something else but doing so may well invalidate your warranty, especially if you choose a low speed fan over whatever fan the VX uses.

kuzzia
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Re: low draw, disable PSU fan Corsair

Post by kuzzia » Wed Apr 20, 2011 10:53 am

how much time do you have left of the warranty?

dhanson865
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Re: low draw, disable PSU fan Corsair

Post by dhanson865 » Wed Apr 20, 2011 3:48 pm

kuzzia wrote:how much time do you have left of the warranty?
At least 2 years, considering how recently the VX450 was released and how long the original warranty was (5 years).

I don't think it's safe to chopstick the fan, though if you want it to be silent or close to it a fan swap is reasonable. You'll void the warranty either way but there is less risk with the fan swap assuming you do it right.

I wouldn't go fanless on that PSU but the closest thing to it would be a swap for a 500RPM slipstream at 12V fixed (instead of wiring it in on the PSUs internal fan connection.)

Next closest to that and slightly more expensive would be a 800RPM S-Flex hard wired to 7V or a Nexus 1000 RPM, S-Flex 1200RPM or even 1600RPM S-Flex hard wired to 5V. (Ironic that a 1600 RPM S-Flex and 1000 RPM Nexus spin at similar enough speeds at 5V to be practically interchangeable for casual use).

If you wanted to wire it into the fan controller just like the original fan was I'd go for the 1600 RPM S-Flex as it'd be nearly silent at idle and still be reasonable for loaded use if you change your config later or sell the PSU to a friend or what not. Most importantly it has a starting voltage low enough to work when the PSU is in the mid wattage ranges.

My Seasonic PSUs fan is doing about 675RPM right now fwiw (I'm guessing your PSU fan is hanging around there as well). Anything in the 400 to 500 RPM range would be an very noticeable improvement over a questionable fan at higher RPMs and it'd be safer than trying to run the PSU fanless.

Assuming you have the same fan as the SPCR review it is a 2050 RPM fan BTW and at idle the VX450 runs that fan at just over 4V. That means any really low RPM fan won't start until the PSU is over 200W or possibly won't start in time or spin fast enough to stop the PSU from overheating in the 300W to 500W range.

120 X 120 X 25 AD1212MB-A71GL BALL Bearing 12V 0.33A 3.96W 2050 RPM 80.5 CFM from http://www.addausa.com/specifications/92-120.pdf and http://www.silentpcreview.com/article751-page3.html
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dan
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Re: low draw, disable PSU fan Corsair

Post by dan » Thu Apr 21, 2011 5:39 am

kuzzia wrote:how much time do you have left of the warranty?
good question

dan
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Re: low draw, disable PSU fan Corsair

Post by dan » Thu Apr 21, 2011 5:42 am

dhanson865 wrote:
kuzzia wrote:how much time do you have left of the warranty?
At least 2 years, considering how recently the VX450 was released and how long the original warranty was (5 years).

I don't think it's safe to chopstick the fan, though if you want it to be silent or close to it a fan swap is reasonable. You'll void the warranty either way but there is less risk with the fan swap assuming you do it right.

I wouldn't go fanless on that PSU but the closest thing to it would be a swap for a 500RPM slipstream at 12V fixed (instead of wiring it in on the PSUs internal fan connection.)

Next closest to that and slightly more expensive would be a 800RPM S-Flex hard wired to 7V or a Nexus 1000 RPM, S-Flex 1200RPM or even 1600RPM S-Flex hard wired to 5V. (Ironic that a 1600 RPM S-Flex and 1000 RPM Nexus spin at similar enough speeds at 5V to be practically interchangeable for casual use).

If you wanted to wire it into the fan controller just like the original fan was I'd go for the 1600 RPM S-Flex as it'd be nearly silent at idle and still be reasonable for loaded use if you change your config later or sell the PSU to a friend or what not. Most importantly it has a starting voltage low enough to work when the PSU is in the mid wattage ranges.

My Seasonic PSUs fan is doing about 675RPM right now fwiw (I'm guessing your PSU fan is hanging around there as well). Anything in the 400 to 500 RPM range would be an very noticeable improvement over a questionable fan at higher RPMs and it'd be safer than trying to run the PSU fanless.

Assuming you have the same fan as the SPCR review it is a 2050 RPM fan BTW and at idle the VX450 runs that fan at just over 4V. That means any really low RPM fan won't start until the PSU is over 200W or possibly won't start in time or spin fast enough to stop the PSU from overheating in the 300W to 500W range.

120 X 120 X 25 AD1212MB-A71GL BALL Bearing 12V 0.33A 3.96W 2050 RPM 80.5 CFM from http://www.addausa.com/specifications/92-120.pdf and http://www.silentpcreview.com/article751-page3.html
\

I think I bought it when it first came out. I think if i check my newegg account where i bought it they have a record.


What about system draw? I use an undervolted c2duo 1.86ghz 65nm 1.18volt with passively cooled nvidia gsts 7600. 1 hd, msi 975x

dhanson865
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Re: low draw, disable PSU fan Corsair

Post by dhanson865 » Thu Apr 21, 2011 6:03 am

dan wrote:What about system draw? I use an undervolted c2duo 1.86ghz 65nm 1.18volt with passively cooled nvidia gsts 7600. 1 hd, msi 975x
I don't know how much power that uses, check with your local library to see if they loan out a Kill-a-watt meter or equivalent. If not the library ask friends and coworkers. Worst case it's $15 to $20 to buy one and wait for it to show up in the mail.

A picoPSU-90 is $40 + a brick you may have laying around or $20 to buy one. Amazon has the picoPSU-90 + brick in a kit for $52 with free shipping.

picoPSU-150 is $50 + a brick, something more like $80 for a kit.

seasonic x-400 is $130
seasonic x-560 is $135

you just missed a sale where the X-650 was $99 at newegg.

Just tossing those out there in case you aren't in the mood to fan swap.
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dan
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Re: low draw, disable PSU fan Corsair

Post by dan » Thu Apr 21, 2011 8:21 am

dhanson865 wrote:
dan wrote:What about system draw? I use an undervolted c2duo 1.86ghz 65nm 1.18volt with passively cooled nvidia gsts 7600. 1 hd, msi 975x
I don't know how much power that uses, check with your local library to see if they loan out a Kill-a-watt meter or equivalent. If not the library ask friends and coworkers. Worst case it's $15 to $20 to buy one and wait for it to show up in the mail.

A picoPSU-90 is $40 + a brick you may have laying around or $20 to buy one. Amazon has the picoPSU-90 + brick in a kit for $52 with free shipping.

picoPSU-150 is $50 + a brick, something more like $80 for a kit.

seasonic x-400 is $130
seasonic x-560 is $135

you just missed a sale where the X-650 was $99 at newegg.

Just tossing those out there in case you aren't in the mood to fan swap.
That's an interesting idea. I'll ask. What do typical pc's that are not overclocked and not SLI draw?

djkest
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Re: low draw, disable PSU fan Corsair

Post by djkest » Thu Apr 21, 2011 8:46 am

dan wrote: That's an interesting idea. I'll ask. What do typical pc's that are not overclocked and not SLI draw?
That's kind of broad.

For example. A 6-core AMD CPU, 2 hard drives, nVidia GTX 580 would draw 200+ at idle and 500+ on load. Not overclocked.

A Quad Core i7, HD 6970 system would probably draw 150W idle and 300+ load

Biggest factor is probably actually the video card, and I'm not sure what an average video card is.

For a non-gaming office-type machine with modern hardware, probably around 50-100 W idle and under 200W with a full load.

dhanson865
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Re: low draw, disable PSU fan Corsair

Post by dhanson865 » Thu Apr 21, 2011 12:34 pm

dan wrote:That's an interesting idea. I'll ask. What do typical pc's that are not overclocked and not SLI draw?
http://www.silentpcreview.com/article28-page4.html shows a few configurations with a low of 54W DC idle / and a high of 102W DC load ( 71W AC / 126W AC with the PSU used in that test). That's with components that aren't chosen for quiet or energy efficient use.

You say you are undervolting with a modern CPU. It could be less. Hard to say without grabbing a meter and testing.

Take a look at viewtopic.php?f=6&t=3075&start=240 and we see
mark19891989 wrote:I have 2 pcs running form 150w pico psu xt, and a dell Da-2

specs:

Desktop:
MB: Asus P5KPL-AM iG31
CPU: e5200 @ 3.75ghz
ram: 4gb DDR2 800 - running at ddr 1000
Storage: 30gb OCZ Vertex ssd
GPU: Nvidia 7300GS

Desktop Power Consumption:
Idle 52w
Load 94w


Server:
MB:Asus P5KPL-AM iG31
CPU: e5200 @ 3ghz
ram: 4gb ddr 800
Storage: 1tb Hitachi DeskStar 1TB 7200 , suspended
GPU: Nvidia 7300GS
Haupage Wintv 150

Server Power Consumption
Idle 58w
Load 89w


All measurements taken at the plug using a kill-a-watt like device.

Desktop:
MB: DFI Lanparty JR P45-T2RS
CPU: e5200 @ 4ghz
ram: 4gb DDR2 800
Storage: 30gb OCZ Vertex ssd
GPU: Nvidia 7300GS
Cooling:
Pump MCP355 with XSPC Res top
CPU BLOCKD-tek fuzion V2
RES: XSPC RS360 RAD

Power usage at load 125-130W , measured at plug again
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