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CNPS2X (cpu fan) on a E3-1270v2


Jiv_au
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Fan On mobo

Hi all.

 

I read overcoat's post on an Active CPU cooling for Gen8 and decided to try it out.

 

Firstly, my spec:

  • Intel Xeon E3-1270v2 - TDP 69 watts, Max. recomm. temp 69c
  • Zalman CNPS2X CPU fan (LGA775/1155) - rated to perform with 120 watts TDP CPU.
  • Kingston KVR1333D3E9SK2 (8GB x 2)
  • Seagate 4TB x 1 - 8 watts
  • A-RAM 120GB SSD x 1 - 1.5 watts
  • Gigabyte HD 6450 - ??? watts
  • Ubuntu 14.04

As the Gen8 PSU is rated to a max of merely 150 watts only, the wattage usage was important to keep in mind.

 

My conclusion is as follows:

 

Any dedicated CPU fan solution is imperfect given the unique 75x65mm dimension of the screw points for heatsink/fan on Gen8

A CPU fan for LGA1155 will probably not be able to be screwed down, because the holes are 75x75mm, and the holes in the Gen8 mobo are 75x65mm.  The LGA775 (72x72mm) comes close, but can only be screwed down on two points at diagonal ends. Even then, there is a difference of 2.6mm, which may be overcome by bending or widening the holes on the fan.

 

Fiddling with wire and soldering is required for sourcing power and PWM for the CPU fan

As overcoat's post has shown, one needs to do their own wiring work as there are no other spare 4-pin (12v/Gnd/PWM/Sensor).

Following overcoat's advice I sourced the 12v and Gnd from the molex, and soldered the PWM to the main fan. Taco (aka sensor or RPM) was left out as it wasn't needed.

 

Higher than recommended CPU temp appears to be caused by issues with Zalman CNPS2X

People who've tried out this product have suggested not using it for any CPU with more than 100w TDP rating.

Also this fan has a "pipe" running through the base, thus not allowing it to lay flat on the CPU, which could be the cause of such high CPU temp. See pictures below.

 

Power consumption of 100 watts

During CPU stress test (on all '8' logical cores - 4 cores with hyper-threading) the power consumption was only 100 watts so there is ample room for other devices (e.g. better graphics card, more HDD).

 

 

Here is the CPU temperature graph while stress testing (using the command "stress -c 8" on my Ubuntu system).

Fan mode was set to Increased Cooling, room temp 20c.

 

E3 1270v2 stress 8cores

 

This is almost 10c higher than the recommendation (69c).

 

The Zalman CPU fan has a bit of an issue where the base surface that contacts the CPU is not quite flat, as shown in the pics below.

This is because there is a "pipe" running through the middle of the square base, which is supposedly there to take the heat directly to the radiators/fins around the fan.

 
This pic shows that the pipe through the middle is raised, thus allowing gaps on both sides.

Fan gap2

 
This pic is to show what may happen when one side is secured down - a bigger gap appears on the other side.

Fan gap1

 

 

And so this is what actually happened...

Start with the thermal paste - note how I've done it slightly diagonal as the Zalman fan will be screwed down only on two points and will be at a slight angle.

ThPaste

 
And here is the GAP between the base of the fan and the CPU.

Cpu Fan Gap

 

One good thing is that there is plenty of space between the top of the fan and the HDD casing within to allow for sufficient airflow.

installed

 
Zalman CNPS2X vs Stock Gen8 CPU heatsink

heatsink Vs Fan 2

heatsink Vs Fan 1

Edited by Jiv_au
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I believe you used waaaaay too much thermal paste on the CPU. You only want 1 very thin line down the middle. That could affect the operating temperature.

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I believe you used waaaaay too much thermal paste on the CPU. You only want 1 very thin line down the middle. That could affect the operating temperature.

 

Due to the gap created by the product design, a "pipe" through the middle of the base that makes the base uneven when placed on the CPU, I was worried that I would not have enough paste.

I think the excess paste oozing out of only the said gap is an indication of how uneven its base surface is.

 

I might have to start considering lapping the bottom of the fan base if the paste doesn't break in properly after some use and the temp doesn't go down.

 

Thanks for the nice pictures. I'm surprised what's possible with a 150 W power supply.

 

No problem.

But 50w to spare is probably not a comfortable margin, given that the video card and I/O was mostly idle through the test and there's only two drives in operation.

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I might have to start considering lapping the bottom of the fan base if the paste doesn't break in properly after some use and the temp doesn't go down.

 

I think lapping would be a good idea.

 

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  • 7 months later...

I'm using the same Zalman CNPS2X - no gaskets - no gaps (only 2 bolts), fan always on full speed. The fan is very quiet. Intel® Xeon® Processor E3-1230 v2 - no limitation of frequency, core and threads.

Edited by AlexS
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  • 2 weeks later...

About the same configuration.

Two diagonal legs cutted down, holes on remain legs extended.

With 1230v2

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