Speed regulation of a replacement fan?

[Chupo]

I have a question about what is going to happen with the fan speeds if I replace the original chipset fan with a different model.

I have DFI Infinity NF ULTRAII-M2 motherboard, the chipset fan is conected directly to the board thru 3 pin FF connector.

When chipset temperature is about 56 C the fan speed is about 4000 rpm. At higher temperatures (65+ C), the speed is more than 6000 rpm.

What I would like to know is what'll happen with the fan speeds if I replace the fan with some model other than original one. Here's one possibility. The specifications say 5000-5499 rpm. What does it mean? Does it mean the speed won't be lower than 5000 rpm even when the temperature is low enough to cool with the 3000 rpm?

I thought the fan speed is voltage controled and the motherboard only changes the voltage according to the chipset temperature. E.g.:

56 C --> 70% of voltage
60 C --> 80% of voltage
62 C --> 90% of voltage
65 C --> 100% of voltage

So if some fan has it's maximum speed 1500 rpm, at 56 C the speed would be 1500*0.7=1050 rpm. Is that correct or am I wrong?

For, I'd like to mount the HR-05 SLI/IFX heatsink (here's another image) and a bigger&slower fan. But I'd also like to preserve the automatic speed control - I don't want to just connect the fan thru molex connector.

I assume the fan has to have 3 pin FF conector (+12 V, GND, sense) and has to be designed for 12 and not 5 V but still wonder if I can be 100% sure the new fan would be electrically compatible with the motherboard's speed control. There was 12 V written on the fan's stick and that was the only way to determine the fan voltage, the voltage is not mentioned in the motherboard's manual.

Now I am not sure if I can mount the heatsink + 8 cm slower fan (instead of 4 cm) and still have the automatic speed regulation. If the maximum speed of 8 cm fan would be 1000 rpm, will it slow down to 700 rpm at 56 C? How I can be sure the power consumption won't be to high?

[Smellydeli]

The specifications say 5000-5499 rpm. What does it mean? Does it mean the speed won't be lower than 5000 rpm even when the temperature is low enough to cool with the 3000 rpm?

From the NewEgg page, it states 4,500k to 5,000k rpm although the difference is probably negligible with such a tiny fan. The advertised speeds are probably the fastest speeds it can spin at, not that it will spin at those rated speeds all the time.

So if some fan has it's maximum speed 1500 rpm, at 56 C the speed would be 1500*0.7=1050 rpm. Is that correct or am I wrong?

The temperature of the chipset is dependent on load, voltage and ambient temperature. That 56C for example would be the idle temp while 65C would be under load. Voltage should not change during this. Fan speed dependent on temperature (if controlled by BIOS to throttle depending on temperature) or to spin at maximum speed all the time or manually controlled.

Just get the Thermalright heatsink and you'll not even need the 80mm fan as the temperature won't get near 56C under load. Don't forget to apply fresh thermal paste.

[Chupo]

The temperature of the chipset is dependent on load, voltage and ambient temperature. That 56C for example would be the idle temp while 65C would be under load. Voltage should not change during this.

I didn't mean that the voltage of the motherboard is changing with the temperature. I am refering the voltage on fan connector, the voltage controled by the motherboard (BIOS) to slow down the fan when the chipset is not too hot. So, motherboard changes the voltage supplied to the fan.

Fan speed dependent on temperature (if controlled by BIOS to throttle depending on temperature) or to spin at maximum speed all the time or manually controlled.

That was my question. If the fan speed is voltage controled then the fan with the fastest speed of let's say 1000 rpm should run slower (e.g. 650 rpm) during the idle because motherboard (BIOS) will lower the voltage supplied to the fan. However, if I mount the fan whose maximum speed is 4000 rpm it will slow down to 2600 rpm (1000/650 = 4000/2600). The motherboard (BIOS) controls the fan speed relatively to it's maximum speed (via controling the supplied voltage), that was what I wanted to be 100% sure before buying a new fan.

Just get the Thermalright heatsink and you'll not even need the 80mm fan as the temperature won't get near 56C under load. Don't forget to apply fresh thermal paste.

It might be so but why not install some slow&quiet 8 cm fan, it won't do any harm. Besides, a few days ago I've somewhere read someone's temperature with the HR-05 was exactly the same as was with the stock cooler + vent. I'll try to find the description.

So I believe my assumptions were right, I just have to find slow&quiet 8 cm fan with +12 V, GND and sense pins on FF connector and motherboard (BIOS) will be able to control the fan speed just as with the stock fan - the only difference will be the maximum speed under load (and, of course, slower speeds as the percentage of maximum speed).

Thank you very much for answering me!

Regards,

[Chupo]

Just get the Thermalright heatsink and you'll not even need the 80mm fan as the temperature won't get near 56C under load. Don't forget to apply fresh thermal paste.

You were right!! :-) Here's the picture of the heatsink right after the mounting. Here's another one. I had some troubles with removing the thermal paste&glue after dismounting the stock cooler. I used isopropyl alcohol but couldn't do anything. Then I had to use a 'normal' alcohol + toothpick but I was afraid because I didn't know if there're some SMD capacitors under the glue. Here's the picture after much more cleaning (are these two 'bumps' normal?). This is the bottom of the old cooler, you can see what was the problem. You can also see the marks of the SMD elements.

I had some more troubles with the Push Pin Metal Clip that couldn't fit because of one of the MB's capacitors so I used Push-Pin-Type Spring Loaded Clip + M3 screws but still had to be very precise not to touch the capacitor.

The idle temperature is now 44 deg C (without additional fan - as you can see the fan speed is now 0000 :-) ), before it was 56 - 61 degrees C depending of the room temp. The load temperatures were never more than 4-5 degrees higher than idle temperatures so I am very pleased with the HR-05 SLI/IFX.

Thank you,
Regards,

[Smellydeli]

Looks like they added a film to the chip although it's probably not necessary. The bumps are probably just bubbles from the film aging from repeated temperature changes which shouldn't be an issue. Kinda like the stickers on the 4890s, there's bubbles everywhere after prolonged use. The area where the SMDs were touching is just a pad to prevent the chip getting cracked or chipped during installation.

Not familiar with that motherboard but those OST capacitors look like they're in good shape for now!

[Mongo129]

the two lumps you can see on the chipset Chupo are epoxy that is covering some bridges, underneath one of them is the bridge that you need to connect to convert you nfoce4 ultra chipset to an sli chipset, this was a very common mod on the old lanparty nforce 4 ultra boards, some of the later ones cam with epoxy like yours covering the bridges, believe the other one allows for more raid functions but not sure on that.

[Chupo]

Not familiar with that motherboard

Neither am I :-) I still don't know where exactly is located the temperature sensor for the system temperature. Seems as it's somewhere near the upper-left corner - I did some experiments with the hair fan - but I'd still like to know the very exact location.

but those OST capacitors look like they're in good shape for now!

Thanx! The motherboard is on 24/7 since september 2006. I had read the capacitors should be changed with better ones (*) before I bought it but everything seems OK, at least for now.

(*)
Drawback:
1. The speed of chipset fan is too high, chipset cooler should be replaced.
2. OST capacitors should be changed to Japanese made capacitors.

#1 I have done :-)

[Chupo]

the two lumps you can see on the chipset Chupo are epoxy that is covering some bridges, underneath one of them is the bridge that you need to connect to convert you nfoce4 ultra chipset to an sli chipset, this was a very common mod on the old lanparty nforce 4 ultra boards, some of the later ones cam with epoxy like yours covering the bridges, believe the other one allows for more raid functions but not sure on that.

So everything is OK, thanx! I somewhere have the data about the SLI mod. Do you maybe have a close up pictures of the uncovered LanParty nForce4 Ultra bridges? I'd like to see how they look like.