Fan Replacements

[ScarletSwordfish]

My PowerCenter Pro 180 has some loud rattly fans (particularly the PSU fan). I would like to replace them, and have been thinking about using Noctua fans after seeing Action Retro and JDW use them. I gathered the specs on the original fans below (I couldn't find performance for the exact model of the CPU fan so guessed based on similar models).
The same size Noctua fans appear to exceed the originals in airflow but have create less static pressure. Do you think they would still be sufficient for cooling my machine? Is there anything else I should know about replacing the fans? Are there other brands I should look at?

PSU Fan	Case Fan	CPU Fan
Nidec BETA SL	Nidec BETA SL	Nidec BETA SL
D08T-12PH S 67	D08T-12PM S	D06G-12TH 01 BS
12 V DC	12 V DC	12 V DC
0.16 Amp	0.16 Amp	0.16 Amp
80x80x25mm	80x80x25mm	60x60x20mm
max airflow: 0.90 m^3/min	max airflow: 0.75 m^3/min	max airflow: 0.50 m^3/min ?
max static pressure: 25 Pa	max static pressure: 17 Pa	max static pressure: 46 Pa ?
sound level: 26 dBA	sound level: 21 dBA	sound level: 27 dBA ?
rated speed: 2400 RPM	rated speed: 2050 RPM	rated speed: 5800 RPM

 

[ScarletSwordfish]

Well if no one thinks it's a bad idea, I'm gonna go ahead and order some Noctua fans.

 

[Certificate of Excellence]

The way I understand it is when Static Pressure increases, air flow decreases and vice versa - think of a computer case and a straight open path for air to flow right through it (this is your positive static pressure), then stick a bunch of hot componentry like cpu heat sinks, PSUs, pci cards etc. in there. Those "blockages" create friction (& negative pressure) as your intake fan has to move air against and around these components clogging up that once clear straight path. This process increases positive static pressure within the case and slows airflow (remember higher static pressure = slower air flow) which overwhelms a fan with a lower static pressure rating more quickly ultimately heating up your box faster.

SO, static pressure is important to keep in mind and I would try to keep those specs as close as possible especially if you are going to be pushing that box hard (like a gaming build for example). Running intake fans with lower Static pressure just means that they will reach their air flow ceiling (and get hotter) faster.

I know spec-wise its hard to find perfect fans these days for older rigs, so another way to help support positive airflow and manage a low static pressure is to install an outtake fan that is actively pulling hot air out of your box, assisting your intake fan. This can help lower spec'd intake fans keep up with moving out hot case air without it being overwhelmed and static pressure shooting way up. Something as small as a $20 PCI/e/x outtake fan kit can do this, so its not an insurmountable problem; you just want to be cognisant of it and adjust your build strategy if it's needed.

 

[Certificate of Excellence]

Here's a graph for those like me who prefer visual, tactile learning.

You can see that with a very high static pressure of 200pa, airflow is very low around 4 cfm. Conversely, a really low static pressure of say 50pa at 50hz, has a comparatively very high airflow at around 18cfm. This shows how a fan with low Pa ratings will become inefficient more quickly and heat up your box & componentry faster than a higher Pa spec'd fan. Anyhow, hope this helps understanding the importance of Static pressure ratings, what they mean and how they work so you can make the best choices for your stuff. Best of luck to you.