has anyone ever upgraded fans to make a system quieter?

Elf

Storybook / Retired, ex-staff
Feb 4, 2019
792
252
63
Mountain West (US)
It is possible, but a quieter fan may not provide the required airflow at the given pressure it encounters. All physical parameters (dimension, airflow, and static pressure) need to be considered when looking for a replacement, as well as matching electrical characteristics. If you can find a fan that matches those and is also quieter, then you might as well replace it :)
 

weblacky

Active member
Jan 13, 2020
181
45
28
Seattle, WA
Well, this is topic as old as SGIs. Some people claimed they solved this on some stations (O2 and Octane), others show hard numbers that these stated "perfect fans" have either less static pressure or move less air (CFM). Which generally means risk from overheat is higher. Some SGIs run very hot so they don't have much margin. Also some board arrangements, for like the Octane, trigger "Fast fan mode", because SGI later discovered the cooling wasn't sufficient and only MAX cooling would do it. So messing with that WILL cause damage to later-addon graphics cards.

My view is, that the desktop SGI machines were made to sit right next to you and work all day. So if you think they are niosey, I would suggest instead of "changing" the fans...buy replacement fans of the EXACT same model and see what they really sounded like, new. I know ALL 3 fans for like the Octane are still available new from places like eBay for cheap! I know some SGI system fans aren't made any more, for those, it's harder.

The odd thing, I never see people talk about, is your fan noisy because it's always been noisy, or is it noisy to due being 20+ years old?

I never heard about original purchasers complaining about the fans, so I always assumed it was poor logic on secondary owners. Since the fans are older designs, they'd need to be replaced every few years of continuous operation. People seem to want to change the fan model all the time. I don't get that logic (sounds very unempirical), look into cleaning out the system interior and just buy new, duplicate, fans and install them, then you'll know.

I can nearly guarantee you, that it will change in tone or something to be more acceptable (even if it's still loud) that you'll accept the originally designed fan...just as new, instead of worn out.

Also I know buying the CPU cooling fans is harder (again Octane CPU fan is totally still gettable), but for other systems you may have to search. Don't forget the PSU fan, that sucker can get pretty worn as well.

I've been collecting SGIs over 20+ year, I've NEVER changed fans, but due to age I have started buying up either new or NOS fans of the exact model SGI used to do a mass-refurbishment of my collection. Given how little I power them on, I expect these replacement fans will easily be good for another 20-30 years as long as they are turned on occasionally.

Do yourself a favor and lookup the correct OEM fan, and just plan on replacing old fans with new fans of the same model. SGI airflow is complex (unlike PCs of that era). Many of them had special thermodynamic flow models to keep noise down with cooling powerful graphics chips.

Indigo2 Cooling : https://www.mentor.com/products/mechanical/success/thermal-design-silicon-graphics-indigo-workstation
 

siliboi

Member
Jan 4, 2021
82
12
8
Halifax Nova Scotia Canada
very nice thanks bro why does he keep talking about reducing load, doesn't everyone want v12 graphics and a specked out octane lol. Anyway scsi to sd is'nt that kinda slow? I was thinking about getting scsi to ssd but I cant find anything (I know sata is a different instruction set i mean a converter). scsi to cf also seems slow but they dont say the speed of the card. I have no idea what the current scsi to sd speed is limited to either.
 

drmadison

Member
Jun 30, 2020
33
20
8
Yes, a SCSI2SD is MUCH slower than the SCSI in an Octane for any kind of sustained reads. For random IO it's hit-or-miss. SCSI to CF won't be much different. SCSI<->SATA adapters like the ACARD 2160h I have in my Octane2 are amazing, however they're also ridiculously priced now (seriously, there was a 3 year period where they doubled in price each year).

Honestly, for an Octane, I wouldn't risk swapping out the fans.

I do have an O2 that I made nearly silent. It's a 300mhz RM5200 model, so as fast as you can get without a CPU fan (or major mod like the R7k solder jobs some have done...). I replaced the PSU fan w/ a Noctua and it's almost perfectly silent. But it also pushes out notably less air. So to ensure that machine doesn't fry itself I limited it to 6 sticks of RAM (the top 2 sticks in O2s get notably hotter than the others even with the full fan). I also went without internal storage, and run the system off an external SCSI cable to a SCSI2SD. Yes, it's slower than using a "real" harddrive, but it's 1 less piece of heat generation in the machine, and lets me run it without concern of overheating anything. I wouldn't dream of doing a similar swap on my R10k O2 w/ a 15k rpm SCSI drive in it.

So all of this to say... yes you can make them silent. Doing so "safely" means also relegating yourself to a lower spec machine and making trade-offs to do it. The fans are the size they are and with the static pressure values that they use, there aren't many alternatives. So you have to knowingly reduce your cooling capacity to do it.
 
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siliboi

Member
Jan 4, 2021
82
12
8
Halifax Nova Scotia Canada
Yes, a SCSI2SD is MUCH slower than the SCSI in an Octane for any kind of sustained reads. For random IO it's hit-or-miss. SCSI to CF won't be much different. SCSI<->SATA adapters like the ACARD 2160h I have in my Octane2 are amazing, however they're also ridiculously priced now (seriously, there was a 3 year period where they doubled in price each year).

Honestly, for an Octane, I wouldn't risk swapping out the fans.

I do have an O2 that I made nearly silent. It's a 300mhz RM5200 model, so as fast as you can get without a CPU fan (or major mod like the R7k solder jobs some have done...). I replaced the PSU fan w/ a Noctua and it's almost perfectly silent. But it also pushes out notably less air. So to ensure that machine doesn't fry itself I limited it to 6 sticks of RAM (the top 2 sticks in O2s get notably hotter than the others even with the full fan). I also went without internal storage, and run the system off an external SCSI cable to a SCSI2SD. Yes, it's slower than using a "real" harddrive, but it's 1 less piece of heat generation in the machine, and lets me run it without concern of overheating anything. I wouldn't dream of doing a similar swap on my R10k O2 w/ a 15k rpm SCSI drive in it.

So all of this to say... yes you can make them silent. Doing so "safely" means also relegating yourself to a lower spec machine and making trade-offs to do it. The fans are the size they are and with the static pressure values that they use, there aren't many alternatives. So you have to knowingly reduce your cooling capacity to do it.
ya I found one scsi to sata on ebay.........$2..........0......0.......0....:O BANANAS
 

Elf

Storybook / Retired, ex-staff
Feb 4, 2019
792
252
63
Mountain West (US)
Unfortunately that is one of ACARD's products that is for IDE optical drives only (CD-ROM drives). They have others that are for regular IDE hard drives which may work for what you are suggesting, but as noted they are very expensive, and stacking adapters may create issues both electrical and physical...
 
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weblacky

Active member
Jan 13, 2020
181
45
28
Seattle, WA
The unit model ending in 22 is for optical drives only, don’t be fooled (look up product manual:
https://www.manualslib.com/manual/1473799/Acard-Aec-7722.html). Sgi depot has info on these as well.

I think you have to have a 7720? Also with these you cannot use them in SCA reliant SGIs. Because these make the drives longer with the adapter board so they won’t fit in drives with SCA sleds (O2, Octane, Tezro, etc).

That’s where these sellers get you, it’s your job to know these aren’t for hard drives (not theirs).

Keep looking :)
 
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siliboi

Member
Jan 4, 2021
82
12
8
Halifax Nova Scotia Canada
The unit model ending in 22 is for optical drives only, don’t be fooled (look up product manual:
https://www.manualslib.com/manual/1473799/Acard-Aec-7722.html). Sgi depot has info on these as well.

I think you have to have a 7720? Also with these you cannot use them in SCA reliant SGIs. Because these make the drives longer with the adapter board so they won’t fit in drives with SCA sleds (O2, Octane, Tezro, etc).

That’s where these sellers get you, it’s your job to know these aren’t for hard drives (not theirs).

Keep looking :)
well son of a gun lol thanks for the info
 

stormy

Active member
Jun 23, 2019
133
55
28
By the way in that forum post about making the octane quieter it isn't about making it silent, just a bit quieter. The fans they talk about are safe to use and push enough air. I know cause I'm one of them in the thread and I assure you my octane runs like a dream. Still noisy compared to a modern pc mind you, but a lot better than the stock fans.
 

siliboi

Member
Jan 4, 2021
82
12
8
Halifax Nova Scotia Canada
By the way in that forum post about making the octane quieter it isn't about making it silent, just a bit quieter. The fans they talk about are safe to use and push enough air. I know cause I'm one of them in the thread and I assure you my octane runs like a dream. Still noisy compared to a modern pc mind you, but a lot better than the stock fans.
which post I couldn't find it and which fans did you use
 

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