80 mm CPU fan - worth replacing with 120 mm?

[Palek]

Hey masters of cooling!

Sorry if I am asking a question that has been answered already, but I did a few searches and could not find anything relevant. I suspect that there is someone out there who has already done what I am planning to do, and I wanted to get their opinions. But any input will be appreciated.

So, the issue is: I have an Alpha PAL 8045 cooling my Athlon 2400+ with a 4000 rpm 80 mm delta fan sitting on top of it. It is quite a noisy beast, so I was wondering if there was a way to replace it with something quieter that would provide similar cooling performance, and naturally a lower-speed 120 mm fan came to mind.

My question(s) is(/are): using an 80 mm to 120 mm adaptor and a 2000 rpm 120 mm fan, would my CPU cooler become any quieter? Does the adaptor add to the noise level? Is there a specific adaptor I should be looking for? Does it matter what material the adaptor is made of? Is plastic okay? Should I seal the gap between the adaptor and the fan to stop the air from being pulled in through there and adding more noise?

Thanks in advance!

 

[CoBRaXT]

Personally, I haven't seen an 80 to 120mm fan adaptor.
But if you can find one, the sound that a 120mm fan makes is drastically lower than an 80mm while pushing a lot more air.
I used to use a 60mm to 80mm fan adaptor and it quieted down the system quite a bit.
The material shouldn't matter - plastic would work fine.

David

 

[Palek]

Thanks, David.

As a matter of fact, I just found an 80 mm to 120 mm converter in a shop the other day. I was tempted to buy it but I thought I should do a little more research.

 

[0roo0roo]

i think svc or case-mod have those adaptors. i'd run the 120mm slightly slower to lower noise even more. a 2400+ doesn't need excessive cooling, you don't gain anything besides noise. single fans suck at fighting backpressure, any resistence and they give up. thats why a fan adaptor will not give you as much of an improvement as you'd think, but it'll still do the job with less noise probably. a 5 dollar fanmate 1 fanspeed controller might let you dial it down to just the right speed.

 

[Palek]

Thanks, OrooOroo.

I am probably getting around 60-65 cfm with the 80 mm 4000 rpm Delta, and the reason why I don't want to go any slower than that is that according to the latest MBM (which can read the diode accurately on my A7N8X) my CPU hovers around 60 degrees celsius at full load, and it's not even summer yet. I really do not want it to go much higher than that (even though there is quite a bit more headroom), that is why I am looking at something that will give me the same throughput at lower noise levels.

Are you saying that the adaptor will significantly inhibit airflow?

 

[scdill]

I made my own adapter/funnel out of poster board. It looks kind of like the container used for Chinese carry-out, 120mm square on the fan end tapering down to 70mm on the heat sink end with an overall height of about 100mm. I then mounted (duct taped) the adapter/funnel to the fan and mounted the fan to the frame above the heat sink (I used the frame so that I can take the side panel off and still operate the system). While I'm evaluating the results, I'm using a piece of cardboard with a 120mm hole in it for the side panel.
Results so far look good. I'm overclocking a 1700 Tbred B with an sk-7 to about 2252. The fan I was using just prior to the 120 was a ThermalTake Smart Fan 2, it was keeping my temps in the low 40s while running Prime95. The 120 mm fan (a Delta WFB1212M 34dbA/72cfm) is keeping the temp about the same. The noise is way, way quieter. And, I suspect I can do better. I have not tuned the system fans and currently have a significant positive pressure in the case, which is probably reducing the air that the 120 is pushing through the sk-7. There are also 120s with better dbA/cfm ratios.

 

[pelikan]

Originally posted by: scdill
I made my own adapter/funnel out of poster board. It looks kind of like the container used for Chinese carry-out, 120mm square on the fan end tapering down to 70mm on the heat sink end with an overall height of about 100mm. I then mounted (duct taped) the adapter/funnel to the fan and mounted the fan to the frame above the heat sink (I used the frame so that I can take the side panel off and still operate the system). While I'm evaluating the results, I'm using a piece of cardboard with a 120mm hole in it for the side panel.
Results so far look good. I'm overclocking a 1700 Tbred B with an sk-7 to about 2252. The fan I was using just prior to the 120 was a ThermalTake Smart Fan 2, it was keeping my temps in the low 40s while running Prime95. The 120 mm fan (a Delta WFB1212M 34dbA/72cfm) is keeping the temp about the same. The noise is way, way quieter. And, I suspect I can do better. I have not tuned the system fans and currently have a significant positive pressure in the case, which is probably reducing the air that the 120 is pushing through the sk-7. There are also 120s with better dbA/cfm ratios.

So you made a duct to a 120mm fan that you plan to mount on your side panel and are testing it first with a cardboard side panel to make sure it works? That's really smart to test it like that.
My cpu fan is on my heatsink and I put a duct from there out my side panel. So with my duct, negative case pressure makes a huge difference in temps because my case fans will pull more air through the duct. I like the idea of putting a 120mm on the side panel though. More cfm at the same noise and with the fan away from the heatsink you get rid of the dead air spot under the fan hub. I may try this some day.

 

[scdill]

Originally posted by: pelikan

Originally posted by: scdill
I made my own adapter/funnel out of poster board. It looks kind of like the container used for Chinese carry-out, 120mm square on the fan end tapering down to 70mm on the heat sink end with an overall height of about 100mm. I then mounted (duct taped) the adapter/funnel to the fan and mounted the fan to the frame above the heat sink (I used the frame so that I can take the side panel off and still operate the system). While I'm evaluating the results, I'm using a piece of cardboard with a 120mm hole in it for the side panel.
Results so far look good. I'm overclocking a 1700 Tbred B with an sk-7 to about 2252. The fan I was using just prior to the 120 was a ThermalTake Smart Fan 2, it was keeping my temps in the low 40s while running Prime95. The 120 mm fan (a Delta WFB1212M 34dbA/72cfm) is keeping the temp about the same. The noise is way, way quieter. And, I suspect I can do better. I have not tuned the system fans and currently have a significant positive pressure in the case, which is probably reducing the air that the 120 is pushing through the sk-7. There are also 120s with better dbA/cfm ratios.

So you made a duct to a 120mm fan that you plan to mount on your side panel and are testing it first with a cardboard side panel to make sure it works? That's really smart to test it like that.
My cpu fan is on my heatsink and I put a duct from there out my side panel. So with my duct, negative case pressure makes a huge difference in temps because my case fans will pull more air through the duct. I like the idea of putting a 120mm on the side panel though. More cfm at the same noise and with the fan away from the heatsink you get rid of the dead air spot under the fan hub. I may try this some day.

I really like the looks of your system. It was what got me started on mine, so thanks for putting the pictures up.

I don't plan on mounting the fan to the side panel, rather I drilled a couple of 1/4" holes in the backside frame, secured a couple of 7.5" bolts parallel to the motherboard, and then sandwiched the fan between the bolts. The mount between the fan and bolts is a real hack (cable ties), but it is super stable with the other end of the duct notched and hooked over the heatsink. The sidepanel pushes up against the fan when mounted. Lets me run the system with the sidepanel on or off.

 

[pelikan]

Originally posted by: scdill

Originally posted by: pelikan

Originally posted by: scdill
I made my own adapter/funnel out of poster board. It looks kind of like the container used for Chinese carry-out, 120mm square on the fan end tapering down to 70mm on the heat sink end with an overall height of about 100mm. I then mounted (duct taped) the adapter/funnel to the fan and mounted the fan to the frame above the heat sink (I used the frame so that I can take the side panel off and still operate the system). While I'm evaluating the results, I'm using a piece of cardboard with a 120mm hole in it for the side panel.
Results so far look good. I'm overclocking a 1700 Tbred B with an sk-7 to about 2252. The fan I was using just prior to the 120 was a ThermalTake Smart Fan 2, it was keeping my temps in the low 40s while running Prime95. The 120 mm fan (a Delta WFB1212M 34dbA/72cfm) is keeping the temp about the same. The noise is way, way quieter. And, I suspect I can do better. I have not tuned the system fans and currently have a significant positive pressure in the case, which is probably reducing the air that the 120 is pushing through the sk-7. There are also 120s with better dbA/cfm ratios.

So you made a duct to a 120mm fan that you plan to mount on your side panel and are testing it first with a cardboard side panel to make sure it works? That's really smart to test it like that.
My cpu fan is on my heatsink and I put a duct from there out my side panel. So with my duct, negative case pressure makes a huge difference in temps because my case fans will pull more air through the duct. I like the idea of putting a 120mm on the side panel though. More cfm at the same noise and with the fan away from the heatsink you get rid of the dead air spot under the fan hub. I may try this some day.

I really like the looks of your system. It was what got me started on mine, so thanks for putting the pictures up.

I don't plan on mounting the fan to the side panel, rather I drilled a couple of 1/4" holes in the backside frame, secured a couple of 7.5" bolts parallel to the motherboard, and then sandwiched the fan between the bolts. The mount between the fan and bolts is a real hack (cable ties), but it is super stable with the other end of the duct notched and hooked over the heatsink. The sidepanel pushes up against the fan when mounted. Lets me run the system with the sidepanel on or off.

Oh. Nice to have the flexibility of being able to run with the side panel on or off.

 

[0roo0roo]

Originally posted by: Palek
Thanks, OrooOroo.

I am probably getting around 60-65 cfm with the 80 mm 4000 rpm Delta, and the reason why I don't want to go any slower than that is that according to the latest MBM (which can read the diode accurately on my A7N8X) my CPU hovers around 60 degrees celsius at full load, and it's not even summer yet. I really do not want it to go much higher than that (even though there is quite a bit more headroom), that is why I am looking at something that will give me the same throughput at lower noise levels.

Are you saying that the adaptor will significantly inhibit airflow?

probably will. you can however run fans in series, one on topof another to fight back pressure more effectively.

 

[Palek]

Last weekend I bought the adaptor and a 1300 rpm 120 mm fan and installed them. The computer is so quiet now I can hear the hard drives, which is remarkable considering both my hard drives are extremely quiet models. The CPU temperature at full load did climb to 66 degrees celsius, but I think I could shave off a few degrees if I made my own adaptor. The one I bought is just way too low and puts the CPU fan right in front of a rear exhaust fan. Should have thought of that beforehand, huh.

Anyway, thanks for all the input!

 

[chocoruacal]

Originally posted by: Palek
Hey masters of cooling!

My question(s) is(/are): using an 80 mm to 120 mm adaptor and a 2000 rpm 120 mm fan, would my CPU cooler become any quieter? Does the adaptor add to the noise level? Is there a specific adaptor I should be looking for? Does it matter what material the adaptor is made of? Is plastic okay? Should I seal the gap between the adaptor and the fan to stop the air from being pulled in through there and adding more noise?

Thanks in advance!

Waste of time/money. There are sooooo many quiet 80mm fans out there to choose from, whats the point?

 

[Mday]

it's not worth it. if you really want some extra cooling, maybe get a duct that brings fresh air to the fan.

my slk800 with a slow rpm 80mm fan on an xp2400+ idles in the low to mid 30s, and goes to high 30s during gaming. i have rarely seen any 40s yet. celcius, btw.

i have 2 120mm fans bringing in fresh air. both are on 5vdc.

 

[amcdonald]

Ducting air to the cpu is the way to go.
I have an 80mm fan to 92mm HSF side panel duct on my slk900u using dryer vent.
Here's some temps for my 2100+ @ 1.8v on an a7n8x, always at load (SOB)
Ambient temp is ~23ºC
Cpu/MB temps: 33ºC/29ºC

 

[Palek]

Chocoruacal, the point is that a slow 120 mm fan can push as much air as a fast 80 mm fan.
Mday and amcdonald, are you sure you are getting temp readouts from the CPU diode? Your temp readings seem ridiculously low. Did you pick the W83L785TS-S diode in MBM?

As for the air duct, I thought about it and might actually do it, although there is way too much dust in the air around here, so I am kind of hesitant to open up another hole on the case to pull in more dust-filled air...

 

[amcdonald]

Palek, I'm using asus probe.
If you are concerned about dust put a good filter on the intake.
Its gonna come in from somewhere anyway.

 

[pelikan]

I may try an air conditioner filter in my duct. I have an air compressor, so its easy to blow out my case, but I'd rather not have to do it every month.
Asus probe reads the socket temp. With my system, the diode reading from MBM5 is 10C higher than the socket reading from asus probe.

 

[Palek]

Not only is the temp readout 10 C lower in Asus Probe, it also reacts to temperature changes much more slowly since it reads the regular socket sensor which works with a relatively big lag.

Regarding dust... I have read a couple articles on the net which suggested vacuuming or blowing out your case to clean it might not be very good for all that sensitive electronic equipment inside. The reason is that fast-moving dust particles create static electricity discharges, and as we already know, static electricity can quite easily kill components in your machine.

Why can't we just take a computer and wash it in the shower?... Dust is my greatest enemy...

I'll give that home-built adaptor ring a shot, see how it works, and of course report back with the results.

 

[soja]

A little late but I made a 120mm to 60mm adapter on my sk6 a while back. Used a large plastic cup like bowl which matched the ring of my 120mm perfectly. The fan was fairly loud (deep roar) since it was a 100cfm 120mm I already had, but nothing compared to the loud whine of the 60mm delta screamer that was on before. Temps came out to be about the same.

 

[Palek]

Not late at all, soja! Thanks for the input! I went to a huge DIY shop to look for something that would work as an adaptor, but could not find anything, so I went with acrylic in the end. I came up with the design for the adaptor already, now I just have to cut the bits and stick them all together...