[KayBee]

Hi All,

In case others are interested, I did some measurements and posted a separate thread here. I took measurements of my Octane in three states and two positions:

1. stock Octane, measured from front and top
2. Octane with restrictive aluminum baffle removed and HDD fan changed, measured from front and top
3. as above with stock Cherokee fan replaced with Scythe, measured from front and top

The changes made a big difference. I followed JacquesT lead with fan choices. His post on silencing an Octane is great and my octane is quieter than my sons PC.

Caveats: 
1. Removing the restrictive front baffle plate exposes some points with nasty powerful electricity. I will operate with the front cover on all the time and actually will probably 3d print small caps to go over the pairs of posts (being sure to unplug and drain all power from the machine first)
2. My machine is now a single R12k 400, with SE Graphics, 1 HDD and no PCI cards, so the load on the machine seems to agree with the fan choices. I'll reduce the load further when I get the SCSI2SD working.

Cheers cool people.

KB

[stormy]

Good work... I did the exact same process except I used a 3000rpm Noctua industrial fan for the PSU. I did try the Scyth but for some reason the PSU would emit a high pitched whistling noise when it was installed, it did this with an arctic cooling fan too - very strange. But yeah, no issues with the noctua.

[KayBee]

Thanks. Good to know, I like Noctua actually, I use them in many (non-SGI) machines I built for clients in quiet environs. I used to use Fractal v2 fans, which were discontinued.

Cheers,

KB

[jan-jaap]

I like Noctua fans, but be careful. I replaced the fans in my Cisco WSC-1400 with Noctuas and the damn thing overheated and several fiber transceivers didn't work until it had cooled down again. The Noctuas were supposed to be within 20% of the original fans.

So I'm not going to put them in my SGIs.

[Jacques]

Noctua fans are quiet and move air OK, but they have shite static pressure values. For sgi machines, you have to consider the static pressure rating of the fan as well as the cf/m ratings. High static pressure allows the fan to draw air over and past components, cfm just tells you how much volume the fan shifts.

[stormy]

You might not be aware but Noctua don't just do 'silent pc fans' but they have an 'industrial' range, here is the spec of the one I use:
https://noctua.at/media/blfa_files/infos...eet_en.pdf

Says static pressure is 10.52 mmH2O, is that adequate?

---

Edit: I did a bit of research on the Syth fans and it seems my Noctua has significantly more static pressure:

https://www.tweaktown.com/image.php?imag...w_full.jpg

Clearly states max 2.4 mmH20 for the 1800 model.

---

Jpg found from this review:
https://www.tweaktown.com/reviews/8972/s...index.html

[Jacques]

10.52 is plenty, however, I think you linked the 140mm version, not the 120mm version? The original panaflow only does 7.95 mmH20. The 120mm Noctua NF F12 does 7.65 mmH2O @3000rpm, so about on par with the old Panaflow. I'd suggest you're good with the industrial version, it also pushes about the same cfm than the original, so a good candidate for direct replacement.

---

10.52 is plenty, however, I think you linked the 140mm version, not the 120mm version? The original panaflow only does 7.95 mmH20.  The 120mm Noctua NF F12 does 7.65 mmH2O @3000rpm, so about on par with the old Panaflow. I'd suggest you're good with the industrial version, it also pushes about the same cfm than the original, so a good candidate for direct replacement.

I've got the Scythe Kaze Jyuni Slip Stream 120mm Fan, not the flex. Can't find mmH2O figures for this one, I do know it works well though! The flex pushes 79 cfm, the slipstream 110.

I'm slightly less concerned about static pressure in a low to mid spec Octane tbh than say against an R12k O2. The O2 has a terrible internal layout for moving air around, the Octane has thicker plating + solid chassis and massive vents at the top allowing for heat to naturally rise and dissipate. If you run your system with moderate intensity for an hour and the components aren't hot then you're probably doing OK. The RAM and CPU in my O2 gets hotter than my Octane equivalents.

I have always maintained that if you run dual CPU and MXI/MXE you should up the drivebay fan speed and increase PSU fan speed, especially for the MXI/MXE TMEZZ modules. They get really, really hot. And also bear in mind, as standard the PSU fan only runs at 8v, it changes to 12v when fastfan kicks in.

[ghost180sx]

Kaybe, this is super awesome stuff as I have the same model Octane and was thinking about doing this at some point.

I'm glad you used a 'real' dB meter and not a smartphone!

Can you re-measure your final results at a distance of 1m or ~3'? I noticed you put the dB meter on the top of the chassis and I think your "real world" sound level at 1m away is probably much more realistic. I plan on putting my octane on the floor under my desk.

Also, it should be obvious, but did you make sure the rest of your room was dead silent and shut off everything else you could find?

Thanks and great work!